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Posted to commits@sling.apache.org by ro...@apache.org on 2017/11/07 09:46:56 UTC

[sling-org-apache-sling-jcr-classloader] 08/18: SLING-1316 - Include jackrabbit classloader code to adjust it for Sling needs - code import with first changes.

This is an automated email from the ASF dual-hosted git repository.

rombert pushed a commit to annotated tag org.apache.sling.jcr.classloader-3.1.0
in repository https://gitbox.apache.org/repos/asf/sling-org-apache-sling-jcr-classloader.git

commit c21156ab23710e3ea75712d43b028b779f567291
Author: Carsten Ziegeler <cz...@apache.org>
AuthorDate: Mon Jan 25 12:43:22 2010 +0000

    SLING-1316 -  Include jackrabbit classloader code to adjust it for Sling needs - code import with first changes.
    
    git-svn-id: https://svn.apache.org/repos/asf/sling/trunk/bundles/jcr/classloader@902794 13f79535-47bb-0310-9956-ffa450edef68
---
 pom.xml                                            |  11 -
 .../classloader/internal/ClassLoaderResource.java  | 414 +++++++++++
 .../jcr/classloader/internal/ClassPathEntry.java   | 227 ++++++
 .../internal/DynamicRepositoryClassLoader.java     | 660 +++++++++++++++++
 .../internal/RepositoryClassLoaderFacade.java      |   1 -
 .../internal/URLRepositoryClassLoader.java         | 795 +++++++++++++++++++++
 .../sling/jcr/classloader/internal/Util.java       | 166 +++++
 .../jcr/classloader/internal/net/FileParts.java    | 312 ++++++++
 .../internal/net/JCRJarURLConnection.java          | 289 ++++++++
 .../classloader/internal/net/JCRJarURLHandler.java | 298 ++++++++
 .../classloader/internal/net/JCRURLConnection.java | 778 ++++++++++++++++++++
 .../classloader/internal/net/JCRURLHandler.java    | 147 ++++
 .../jcr/classloader/internal/net/URLFactory.java   |  99 +++
 13 files changed, 4185 insertions(+), 12 deletions(-)

diff --git a/pom.xml b/pom.xml
index 371a03f..5da1fbc 100644
--- a/pom.xml
+++ b/pom.xml
@@ -59,11 +59,6 @@
                         </Bundle-Category>
                         <Private-Package>
                             org.apache.sling.jcr.classloader.internal.*,
-                            org.apache.jackrabbit;
-                            org.apache.jackrabbit.classloader;
-                            org.apache.jackrabbit.name;
-                            org.apache.jackrabbit.net;
-                            org.apache.jackrabbit.util;split-package:=merge-first
                         </Private-Package>
                     </instructions>
                 </configuration>
@@ -115,12 +110,6 @@
             <artifactId>junit</artifactId>
         </dependency>
         <dependency>
-            <groupId>commons-collections</groupId>
-            <artifactId>commons-collections</artifactId>
-            <version>3.2.1</version>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
             <groupId>org.osgi</groupId>
             <artifactId>org.osgi.core</artifactId>
         </dependency>
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/ClassLoaderResource.java b/src/main/java/org/apache/sling/jcr/classloader/internal/ClassLoaderResource.java
new file mode 100644
index 0000000..73671bf
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/ClassLoaderResource.java
@@ -0,0 +1,414 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.security.cert.Certificate;
+import java.util.Date;
+import java.util.jar.Manifest;
+
+import javax.jcr.Property;
+import javax.jcr.RepositoryException;
+
+import org.apache.sling.jcr.classloader.internal.net.URLFactory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+
+/**
+ * The <code>ClassLoaderResource</code> class represents a resource looked up
+ * by the {@link ClassPathEntry}s of the {@link URLRepositoryClassLoader}.
+ */
+class ClassLoaderResource {
+
+    /** default log category */
+    private static final Logger log =
+        LoggerFactory.getLogger(ClassLoaderResource.class);
+
+    /**
+     * The class path entry which loaded this class loader resource
+     */
+    private final ClassPathEntry pathEntry;
+
+    /**
+     * The name of this resource.
+     */
+    private final String name;
+
+    /**
+     * The repository property providing the resource's contents. This may be
+     * <code>null</code> if the resource was loaded from a JAR/ZIP archive.
+     */
+    private final Property resProperty;
+
+    /**
+     * The class optionally loaded/defined through this resource.
+     *
+     * @see #getLoadedClass()
+     * @see #setLoadedClass(Class)
+     */
+    private Class<?> loadedClass;
+
+    /**
+     * The time in milliseconds at which this resource has been loaded from
+     * the repository.
+     */
+    private final long loadTime;
+
+    /**
+     * Flag indicating that this resource has already been checked for expiry
+     * and whether it is actually expired.
+     *
+     * @see #isExpired()
+     */
+    private boolean expired;
+
+    /**
+     * Creates an instance of this class for the class path entry.
+     *
+     * @param pathEntry The {@link ClassPathEntry} of the code source of this
+     *      class loader resource.
+     * @param name The path name of this resource.
+     * @param resProperty The <code>Property</code>providing the content's of
+     *      this resource. This may be <code>null</code> if the resource
+     *      was loaded from an JAR or ZIP archive.
+     */
+    /* package */ ClassLoaderResource(ClassPathEntry pathEntry, String name,
+            Property resProperty) {
+        this.pathEntry = pathEntry;
+        this.name = name;
+        this.resProperty = resProperty;
+        this.loadTime = System.currentTimeMillis();
+    }
+
+    /**
+     * Returns the {@link ClassPathEntry} which loaded this resource.
+     */
+    protected ClassPathEntry getClassPathEntry() {
+        return pathEntry;
+    }
+
+    /**
+     * Returns the name of this resource. This is the name used to find the
+     * resource, for example the class name or the properties file path.
+     */
+    public String getName() {
+        return name;
+    }
+
+    /**
+     * Returns the <code>Property</code> with which this resource is created.
+     */
+    protected Property getProperty() {
+        return resProperty;
+    }
+
+    /**
+     * Returns the time in milliseconds at which this resource has been loaded
+     */
+    protected long getLoadTime() {
+        return loadTime;
+    }
+
+    /**
+     * Returns the URL to access this resource, for example a JCR or a JAR URL.
+     * If the URL cannot be created from the resource data, <code>null</code> is
+     * returned.
+     */
+    public URL getURL() {
+        try {
+            return URLFactory.createURL(getClassPathEntry().session, getPath());
+        } catch (Exception e) {
+            log.warn("getURL: Cannot getURL for " + getPath(), e);
+        }
+        return null;
+    }
+
+    /**
+     * Returns the URL to the code source of this entry. If there is no code
+     * source available, <code>null</code> is returned.
+     * <p>
+     * This base class implementation returns the result of calling
+     * {@link ClassPathEntry#toURL()} on the class path entry from which this
+     * resource was loaded.
+     */
+    public URL getCodeSourceURL() {
+        return getClassPathEntry().toURL();
+    }
+
+    /**
+     * Returns an <code>InputStream</code> to read from the resource.
+     * <p>
+     * This base class implementation returns the result of calling the
+     * <code>getStream()</code> method on the resource's property or
+     * <code>null</code> if the property is not set.
+     */
+    public InputStream getInputStream() throws RepositoryException {
+        return (getProperty() != null) ? getProperty().getStream() : null;
+    }
+
+    /**
+     * Returns the size of the resource or -1 if the size cannot be found out.
+     * <p>
+     * This base class implementation returns the result of calling the
+     * <code>getLength()</code> method on the resource's property or -1 if
+     * the property is not set.
+     *
+     * @throws RepositoryException If an error occurrs trying to find the length
+     *      of the property.
+     */
+    public int getContentLength() throws RepositoryException {
+        return (getProperty() != null) ? (int) getProperty().getLength() : -1;
+    }
+
+    /**
+     * Returns the path of the property containing the resource.
+     * <p>
+     * This base class implementation returns the absolute path of the
+     * resource's property. If the property is not set or if an error occurrs
+     * accesing the property's path, the concatentation of the class path
+     * entry's path and the resource's name is returned.
+     */
+    public String getPath() {
+        if (getProperty() != null) {
+            try {
+                return getProperty().getPath();
+            } catch (RepositoryException re) {
+                // fallback
+                log.warn("getPath: Cannot retrieve path of entry " + getName(),
+                    re);
+            }
+        }
+
+        // fallback if no resource property or an error accessing the path of
+        // the property
+        return getSafePath();
+    }
+
+    /**
+     * Returns the path of the property containing the resource by appending
+     * the {@link #getName() name} to the path of the class path entry to which
+     * this resource belongs. This path need not necessairily be the same as
+     * the {@link #getProperty() path of the property} but will always succeed
+     * as there is no repository access involved.
+     */
+    protected String getSafePath() {
+        return getClassPathEntry().getPath() + getName();
+    }
+
+    /**
+     * Returns the time of the the last modification of the resource or -1 if
+     * the last modification time cannot be evaluated.
+     * <p>
+     * This base class implementation returns the result of calling the
+     * {@link Util#getLastModificationTime(Property)} method on the resource's
+     * property if not <code>null</code>. In case of an error or if the
+     * property is <code>null</code>, -1 is returned.
+     */
+    public long getLastModificationTime() {
+        if (getProperty() != null) {
+            try {
+                return Util.getLastModificationTime(getProperty());
+            } catch (RepositoryException re) {
+                log.info("getLastModificationTime of resource property", re);
+            }
+        }
+
+        // cannot find the resource modification time, use epoch
+        return -1;
+    }
+
+    /**
+     * Returns the resource as an array of bytes
+     */
+    public byte[] getBytes() throws IOException, RepositoryException {
+        InputStream in = null;
+        byte[] buf = null;
+
+        log.debug("getBytes");
+
+        try {
+            in = getInputStream();
+            log.debug("getInputStream() returned {}", in);
+
+            int length = getContentLength();
+            log.debug("getContentLength() returned {}", new Integer(length));
+
+            if (length >= 0) {
+
+                buf = new byte[length];
+                for (int read; length > 0; length -= read) {
+                    read = in.read(buf, buf.length - length, length);
+                    if (read == -1) {
+                        throw new IOException("unexpected EOF");
+                    }
+                }
+
+            } else {
+
+                buf = new byte[1024];
+                int count = 0;
+                int read;
+
+                // read enlarging buffer
+                while ((read = in.read(buf, count, buf.length - count)) != -1) {
+                    count += read;
+                    if (count >= buf.length) {
+                        byte buf1[] = new byte[count * 2];
+                        System.arraycopy(buf, 0, buf1, 0, count);
+                        buf = buf1;
+                    }
+                }
+
+                // resize buffer if too big
+                if (count != buf.length) {
+                    byte buf1[] = new byte[count];
+                    System.arraycopy(buf, 0, buf1, 0, count);
+                    buf = buf1;
+                }
+
+            }
+
+        } finally {
+
+            if (in != null) {
+                try {
+                    in.close();
+                } catch (IOException ignore) {
+                }
+            }
+
+        }
+
+        return buf;
+    }
+
+    /**
+     * Returns the manifest from the jar file for this class resource. If this
+     * resource is not from a jar file, the method returns <code>null</code>,
+     * which is what the default implementation does.
+     */
+    public Manifest getManifest() {
+        return null;
+    }
+
+    /**
+     * Returns the certificates from the jar file for this class resource. If
+     * this resource is not from a jar file, the method returns
+     * <code>null</code>, which is what the default implementation does.
+     */
+    public Certificate[] getCertificates() {
+        return null;
+    }
+
+    /**
+     * Returns the <code>Property</code> which is used to check whether this
+     * resource is expired or not.
+     * <p>
+     * This base class method returns the same property as returned by the
+     * {@link #getProperty()} method. This method may be overwritten by
+     * implementations as appropriate.
+     *
+     * @see #isExpired()
+     */
+    protected Property getExpiryProperty() {
+        return getProperty();
+    }
+
+    /**
+     * Returns <code>true</code> if the last modification date of the expiry
+     * property of this resource is loaded is later than the time at which this
+     * resource has been loaded. If the last modification time of the expiry
+     * property cannot be calculated or if an error occurrs checking the expiry
+     * propertiy's last modification time, <code>true</code> is returned.
+     */
+    public boolean isExpired() {
+        if (!expired) {
+            // creation time of version if loaded now
+            long currentPropTime = 0;
+            Property prop = getExpiryProperty();
+            if (prop != null) {
+                try {
+                    currentPropTime = Util.getLastModificationTime(prop);
+                } catch (RepositoryException re) {
+                    // cannot get last modif time from property, use current time
+                    log.debug("expireResource: Cannot get current version for "
+                        + toString() + ", will expire", re);
+                    currentPropTime = System.currentTimeMillis();
+                }
+            }
+
+            // creation time of version currently loaded
+            long loadTime = getLoadTime();
+
+            // expire if a new version would be loaded
+            expired = currentPropTime > loadTime;
+            if (expired && log.isDebugEnabled()) {
+                log.debug(
+                    "expireResource: Resource created {} superceded by version created {}",
+                    new Date(loadTime), new Date(currentPropTime));
+            }
+        }
+
+        return expired;
+    }
+
+    /**
+     * Returns the class which was loaded through this resource. It is expected
+     * that the class loader sets the class which was loaded through this
+     * resource by calling the {@link #setLoadedClass(Class)} method. If this
+     * class was not used to load a class or if the class loader failed to
+     * set the class loaded through this resoource, this method will return
+     * <code>null</code>.
+     *
+     * @return The class loaded through this resource, which may be
+     *      <code>null</code> if this resource was never used to load a class
+     *      or if the loader failed to set class through the
+     *      {@link #setLoadedClass(Class)} method.
+     *
+     * @see #setLoadedClass(Class)
+     */
+    public Class<?> getLoadedClass() {
+        return loadedClass;
+    }
+
+    /**
+     * Sets the class which was loaded through this resource. This method does
+     * not check, whether it is plausible that this class was actually loaded
+     * from this resource, nor does this method check whether the class object
+     * is <code>null</code> or not.
+     *
+     * @param loadedClass The class to be loaded.
+     */
+    public void setLoadedClass(Class<?> loadedClass) {
+        this.loadedClass = loadedClass;
+    }
+
+    /**
+     * Returns the <code>String</code> representation of this resource.
+     */
+    public String toString() {
+        final StringBuilder buf = new StringBuilder(getClass().getName());
+        buf.append(": path=");
+        buf.append(getSafePath());
+        buf.append(", name=");
+        buf.append(getName());
+        return buf.toString();
+    }
+}
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/ClassPathEntry.java b/src/main/java/org/apache/sling/jcr/classloader/internal/ClassPathEntry.java
new file mode 100644
index 0000000..3f79345
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/ClassPathEntry.java
@@ -0,0 +1,227 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal;
+
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.security.AccessControlException;
+
+import javax.jcr.PathNotFoundException;
+import javax.jcr.Property;
+import javax.jcr.RepositoryException;
+import javax.jcr.Session;
+
+import org.apache.sling.jcr.classloader.internal.net.URLFactory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * The <code>ClassPathEntry</code> class encapsulates entries in the class path
+ * of the {@link DynamicRepositoryClassLoader}. The main task is to retrieve
+ * {@link ClassLoaderResource} instances for classes or resources to load from it.
+ * <p>
+ * This implementation is not currently integrated with Java security. That is
+ * protection domains and security managers are not supported yet.
+ * <p>
+ * This class is not intended to be subclassed or instantiated by clients.
+ */
+public final class ClassPathEntry {
+
+    /** default logging */
+    private static final Logger log =
+        LoggerFactory.getLogger(ClassPathEntry.class);
+
+    /** The session assigned to this class path entry */
+    protected final Session session;
+
+    /** The path to the item of this class path entry */
+    protected final String path;
+
+    /** The base URL for the class path entry to later construct resource URLs */
+    protected URL baseURL;
+
+    //---------- construction --------------------------------------------------
+
+    /**
+     * Creates an instance of the <code>ClassPathEntry</code> assigning the
+     * session and path.
+     *
+     * @param session The <code>Session</code> to access the Repository.
+     * @param path The path of the class path entry, this is either the
+     *      path of a node containing a jar archive or is the path
+     *      of the root of a hierarchy to look up resources in.
+     */
+    protected ClassPathEntry(Session session, String path) {
+        this.path = path;
+        this.session = session;
+    }
+
+    /**
+     * Clones this instance of the <code>ClassPathEntry</code> setting the
+     * path and session to the same value as the base instance.
+     * <p>
+     * Note that this constructor does not duplicate the session from the base
+     * instance.
+     *
+     * @param base The <code>ClassPathEntry</code> from which to copy the path
+     *      and the session.
+     */
+    protected ClassPathEntry(ClassPathEntry base) {
+        this.path = base.path;
+        this.session = base.session;
+        this.baseURL = base.baseURL;
+    }
+
+    /**
+     * Returns an instance of the <code>ClassPathEntry</code> class. This
+     * instance will be a subclass correctly handling the type (directory or
+     * jar archive) of class path entry is to be created.
+     * <p>
+     * If the path given has a trailing slash, it is taken as a directory root
+     * else the path is first tested, whether it contains an archive. If not
+     * the path is treated as a directory.
+     *
+     * @param session The <code>Session</code> to access the Repository.
+     * @param path The path of the class path entry, this is either the
+     *      path of a node containing a jar archive or is the path
+     *      of the root of a hierharchy to look up resources in.
+     *
+     * @return An initialized <code>ClassPathEntry</code> instance for the
+     *      path or <code>null</code> if an error occurred creating the
+     *      instance.
+     */
+    static ClassPathEntry getInstance(Session session, String path) {
+
+        // check we can access the path, don't care about content now
+        try {
+            session.checkPermission(path, "read");
+        } catch (AccessControlException ace) {
+            log.warn(
+                "getInstance: Access denied reading from {}, ignoring entry",
+                path);
+            return null;
+        } catch (RepositoryException re) {
+            log.error("getInstance: Cannot check permission to " + path, re);
+        }
+
+        if (!path.endsWith("/")) {
+            // assume the path designates a directory
+            // append trailing slash now
+            path += "/";
+        }
+
+        // we assume a directory class path entry, but we might have to check
+        // whether the path refers to a node or not. On the other hande, this
+        // class path entry will not be usable anyway if not, user beware :-)
+
+        return new ClassPathEntry(session, path);
+    }
+
+    /**
+     * Returns the path on which this <code>ClassPathEntry</code> is based.
+     */
+    public String getPath() {
+        return path;
+    }
+
+    /**
+     * Returns this <code>ClassPathEntry</code> represented as an URL to be
+     * used in a list of URLs to further work on. If there is a problem creating
+     * the URL for this instance, <code>null</code> is returned instead.
+     */
+    public URL toURL() {
+        if (baseURL == null) {
+            try {
+                baseURL = URLFactory.createURL(session, path);
+            } catch (MalformedURLException mue) {
+                log.warn("DirectoryClassPathEntry: Creating baseURl for " +
+                    path, mue);
+            }
+        }
+
+        return baseURL;
+    }
+
+    /**
+     * Returns a {@link ClassLoaderResource} for the named resource if it
+     * can befound below this directory root identified by the path given
+     * at construction time. Note that if the page would exist but does
+     * either not contain content or is not readable by the current session,
+     * no resource is returned.
+     *
+     * @param name The name of the resource to return. If the resource would
+     *      be a class the name must already be modified to denote a valid
+     *      path, that is dots replaced by dashes and the <code>.class</code>
+     *      extension attached.
+     *
+     * @return The {@link ClassLoaderResource} identified by the name or
+     *      <code>null</code> if no resource is found for that name.
+     */
+    public ClassLoaderResource getResource(final String name) {
+
+        try {
+            final Property prop = Util.getProperty(session.getItem(path + name));
+            if (prop != null) {
+                return new ClassLoaderResource(this, name, prop);
+            }
+
+            log.debug("getResource: resource {} not found below {} ", name,
+                path);
+
+        } catch (PathNotFoundException pnfe) {
+
+            log.debug("getResource: Classpath entry {} does not have resource {}",
+                path, name);
+
+        } catch (RepositoryException cbe) {
+
+            log.warn("getResource: problem accessing the resource {} below {}",
+                new Object[] { name, path }, cbe);
+
+        }
+        // invariant : no page or problem accessing the page
+
+        return null;
+    }
+
+    /**
+     * Returns a <code>ClassPathEntry</code> with the same configuration as
+     * this <code>ClassPathEntry</code>.
+     * <p>
+     * Becase the <code>DirectoryClassPathEntry</code> class does not have
+     * internal state, this method returns this instance to be used as
+     * the "copy".
+     */
+    ClassPathEntry copy() {
+        return this;
+    }
+
+    /**
+     * @see Object#toString()
+     */
+    public String toString() {
+        StringBuilder buf = new StringBuilder(super.toString());
+        buf.append(": path: ");
+        buf.append(path);
+        buf.append(", user: ");
+        buf.append(session.getUserID());
+        return buf.toString();
+    }
+
+    //----------- internal helper ----------------------------------------------
+
+}
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/DynamicRepositoryClassLoader.java b/src/main/java/org/apache/sling/jcr/classloader/internal/DynamicRepositoryClassLoader.java
new file mode 100644
index 0000000..35df60a
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/DynamicRepositoryClassLoader.java
@@ -0,0 +1,660 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+
+import javax.jcr.Property;
+import javax.jcr.RepositoryException;
+import javax.jcr.Session;
+import javax.jcr.observation.Event;
+import javax.jcr.observation.EventIterator;
+import javax.jcr.observation.EventListener;
+import javax.jcr.observation.ObservationManager;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+
+/**
+ * The <code>DynamicRepositoryClassLoader</code> class extends the
+ * {@link org.apache.sling.jcr.classloader.internal.URLRepositoryClassLoader} and provides the
+ * functionality to load classes and resources from the JCR Repository.
+ * Additionally, this class supports the notion of getting 'dirty', which means,
+ * that if a resource loaded through this class loader has been modified in the
+ * Repository, this class loader marks itself dirty, which flag can get
+ * retrieved. This helps the user of this class loader to decide on whether to
+ * {@link #reinstantiate(Session, ClassLoader) reinstantiate} it or continue
+ * using this class loader.
+ * <p>
+ * When a user of the class loader recognizes an instance to be dirty, it can
+ * easily be reinstantiated with the {@link #reinstantiate} method. This
+ * reinstantiation will also rebuild the internal real class path from the same
+ * list of path patterns as was used to create the internal class path for the
+ * original class loader. The resulting internal class path need not be the
+ * same, though.
+ * <p>
+ * As an additional feature the class loaders provides the functionality for
+ * complete reconfiguration of the list of path patterns defined at class loader
+ * construction time through the {@link #reconfigure(String[])} method. This
+ * reconfiguration replaces the internal class path with a new one built from
+ * the new path list and also replaces that path list. Reinstantiating a
+ * reconfigured class loader gets a class loader containing the same path list
+ * as the original class loader had after reconfiguration. That is the original
+ * configuration is lost. While reconfiguration is not able to throw away
+ * classes already loaded, it will nevertheless mark the class loader dirty, if
+ * any classes have already been loaded through it.
+ * <p>
+ * This class is not intended to be extended by clients.
+ */
+public class DynamicRepositoryClassLoader
+    extends URLRepositoryClassLoader
+    implements EventListener {
+
+    /** default log category */
+    private final Logger log =
+        LoggerFactory.getLogger(this.getClass().getName());
+
+    /**
+     * Cache of resources used to check class loader expiry. The map is indexed
+     * by the paths of the expiry properties of the cached resources. This map
+     * is not complete in terms of resources which have been loaded through this
+     * class loader. That is for resources loaded through an archive class path
+     * entry, only one of those resources (the last one loaded) is kept in this
+     * cache, while the others are ignored.
+     *
+     * @see #onEvent(EventIterator)
+     * @see #findClassLoaderResource(String)
+     */
+    private Map modTimeCache;
+
+    /**
+     * Flag indicating whether there are loaded classes which have later been
+     * expired (e.g. invalidated or modified)
+     */
+    private boolean dirty;
+
+    /**
+     * The list of repositories added through either the {@link #addURL} or the
+     * {@link #addHandle} method.
+     */
+    private ClassPathEntry[] addedRepositories;
+
+    private EventListener[] proxyListeners;
+
+    /**
+     * Creates a <code>DynamicRepositoryClassLoader</code> from a list of item
+     * path strings containing globbing pattens for the paths defining the
+     * class path.
+     *
+     * @param session The <code>Session</code> to use to access the class items.
+     * @param classPath The list of path strings making up the (initial) class
+     *      path of this class loader. The strings may contain globbing
+     *      characters which will be resolved to build the actual class path.
+     * @param parent The parent <code>ClassLoader</code>, which may be
+     *      <code>null</code>.
+     *
+     * @throws NullPointerException if either the session or the handles list
+     *      is <code>null</code>.
+     */
+    public DynamicRepositoryClassLoader(Session session,
+            String[] classPath, ClassLoader parent) {
+
+        // initialize the super class with an empty class path
+        super(session, classPath, parent);
+
+        // set fields
+        dirty = false;
+        modTimeCache = new HashMap();
+
+        // register with observation service and path pattern list
+        registerModificationListener();
+
+        log.debug("DynamicRepositoryClassLoader: {} ready", this);
+    }
+
+    /**
+     * Creates a <code>DynamicRepositoryClassLoader</code> with the same
+     * configuration as the given <code>DynamicRepositoryClassLoader</code>.
+     * This constructor is used by the {@link #reinstantiate} method.
+     * <p>
+     * Before returning from this constructor the <code>old</code> class loader
+     * is destroyed and may not be used any more.
+     *
+     * @param session The session to associate with this class loader.
+     * @param old The <code>DynamicRepositoryClassLoader</code> to copy the
+     *            cofiguration from.
+     * @param parent The parent <code>ClassLoader</code>, which may be
+     *            <code>null</code>.
+     */
+    private DynamicRepositoryClassLoader(Session session,
+            DynamicRepositoryClassLoader old, ClassLoader parent) {
+
+        // initialize the super class with an empty class path
+        super(session, old.getPaths(), parent);
+
+        // set the configuration and fields
+        dirty = false;
+        modTimeCache = new HashMap();
+
+        // create a repository from the handles - might get a different one
+        setRepository(resetClassPathEntries(old.getRepository()));
+        setAddedRepositories(resetClassPathEntries(old.getAddedRepositories()));
+        buildRepository();
+
+        // register with observation service and path pattern list
+        registerModificationListener();
+
+        // finally finalize the old class loader
+        old.destroy();
+
+        log.debug(
+            "DynamicRepositoryClassLoader: Copied {}. Do not use that anymore",
+            old);
+    }
+
+    /**
+     * Destroys this class loader. This process encompasses all steps needed
+     * to remove as much references to this class loader as possible.
+     * <p>
+     * <em>NOTE</em>: This method just clears all internal fields and especially
+     * the class path to render this class loader unusable.
+     * <p>
+     * This implementation does not throw any exceptions.
+     */
+    public void destroy() {
+        // we expect to be called only once, so we stop destroyal here
+        if (isDestroyed()) {
+            log.debug("Instance is already destroyed");
+            return;
+        }
+
+        // remove ourselves as listeners from other places
+        unregisterListener();
+
+        addedRepositories = null;
+
+        super.destroy();
+    }
+
+    //---------- reload support ------------------------------------------------
+
+    /**
+     * Checks whether this class loader already loaded the named resource and
+     * would load another version if it were instructed to do so. As a side
+     * effect the class loader sets itself dirty in this case.
+     * <p>
+     * Calling this method yields the same result as calling
+     * {@link #shouldReload(String, boolean)} with the <code>force</code>
+     * argument set to <code>false</code>.
+     *
+     * @param name The name of the resource to check.
+     *
+     * @return <code>true</code> if the resource is loaded and reloading would
+     *      take another version than currently loaded.
+     *
+     * @see #isDirty
+     */
+    public synchronized boolean shouldReload(String name) {
+        return shouldReload(name, false);
+    }
+
+    /**
+     * Checks whether this class loader already loaded the named resource and
+     * whether the class loader should be set dirty depending on the
+     * <code>force</code> argument. If the argument is <code>true</code>, the
+     * class loader is marked dirty and <code>true</code> is returned if the
+     * resource has been loaded, else the loaded resource is checked for expiry
+     * and the class loader is only set dirty if the loaded resource has
+     * expired.
+     *
+     * @param name The name of the resource to check.
+     * @param force <code>true</code> if the class loader should be marked dirty
+     *      if the resource is loaded, else the class loader is only marked
+     *      dirty if the resource is loaded and has expired.
+     *
+     * @return <code>true</code> if the resource is loaded and
+     *      <code>force</code> is <code>true</code> or if the resource has
+     *      expired. <code>true</code> is also returned if this class loader
+     *      has already been destroyed.
+     *
+     * @see #isDirty
+     */
+    public synchronized boolean shouldReload(String name, boolean force) {
+        if (isDestroyed()) {
+            log.warn("Classloader already destroyed, reload required");
+            return true;
+        }
+
+        ClassLoaderResource res = getCachedResource(name);
+        if (res != null) {
+            log.debug("shouldReload: Expiring cache entry {}", res);
+            if (force) {
+                log.debug("shouldReload: Forced dirty flag");
+                dirty = true;
+                return true;
+            }
+
+            return expireResource(res);
+        }
+
+        return false;
+    }
+
+    /**
+     * Returns <code>true</code> if any of the loaded classes need reload. Also
+     * sets this class loader dirty. If the class loader is already set dirty
+     * or if this class loader has been destroyed before calling this method,
+     * it returns immediately.
+     *
+     * @return <code>true</code> if any class loader needs to be reinstantiated.
+     *
+     * @see #isDirty
+     */
+    public synchronized boolean shouldReload() {
+
+        // check whether we are already dirty
+        if (isDirty()) {
+            log.debug("shouldReload: Dirty, need reload");
+            return true;
+        }
+
+        // Check whether any class has changed
+        for (Iterator iter = getCachedResources(); iter.hasNext();) {
+            if (expireResource((ClassLoaderResource) iter.next())) {
+                log.debug("shouldReload: Found expired resource, need reload");
+                return true;
+            }
+        }
+
+        // No changes, no need to reload
+        log.debug("shouldReload: No expired resource found, no need to reload");
+        return false;
+    }
+
+    /**
+     * Returns whether the class loader is dirty. This can be the case if any
+     * of the {@link #shouldReload(String)} or {@link #shouldReload()}
+     * methods returned <code>true</code> or if a loaded class has been expired
+     * through the observation.
+     * <p>
+     * This method may also return <code>true</code> if the <code>Session</code>
+     * associated with this class loader is not valid anymore.
+     * <p>
+     * Finally the method always returns <code>true</code> if the class loader
+     * has already been destroyed. Note, however, that a destroyed class loader
+     * cannot be reinstantiated. See {@link #reinstantiate(Session, ClassLoader)}.
+     * <p>
+     * If the class loader is dirty, it should be reinstantiated through the
+     * {@link #reinstantiate} method.
+     *
+     * @return <code>true</code> if the class loader is dirty and needs
+     *      reinstantiation.
+     */
+    public boolean isDirty() {
+        return isDestroyed() || dirty || !getSession().isLive();
+    }
+
+    /**
+     * Reinstantiates this class loader. That is, a new ClassLoader with no
+     * loaded class is created with the same configuration as this class loader.
+     * <p>
+     * When the new class loader is returned, this class loader has been
+     * destroyed and may not be used any more.
+     *
+     * @param parent The parent <code>ClassLoader</code> for the reinstantiated
+     * 	    <code>DynamicRepositoryClassLoader</code>, which may be
+     *      <code>null</code>.
+     *
+     * @return a new instance with the same configuration as this class loader.
+     *
+     * @throws IllegalStateException if <code>this</code>
+     *      {@link DynamicRepositoryClassLoader} has already been destroyed
+     *      through the {@link #destroy()} method.
+     */
+    public DynamicRepositoryClassLoader reinstantiate(Session session, ClassLoader parent) {
+        log.debug("reinstantiate: Copying {} with parent {}", this, parent);
+
+        if (isDestroyed()) {
+            throw new IllegalStateException("Destroyed class loader cannot be recreated");
+        }
+
+        // create the new loader
+        DynamicRepositoryClassLoader newLoader =
+                new DynamicRepositoryClassLoader(session, this, parent);
+
+        // return the new loader
+        return newLoader;
+    }
+
+    //---------- URLClassLoader overwrites -------------------------------------
+
+    /**
+     * Reconfigures this class loader with the pattern list. That is the new
+     * pattern list completely replaces the current pattern list. This new
+     * pattern list will also be used later to configure the reinstantiated
+     * class loader.
+     * <p>
+     * If this class loader already has loaded classes using the old, replaced
+     * path list, it is set dirty.
+     * <p>
+     * If this class loader has already been destroyed, this method has no
+     * effect.
+     *
+     * @param classPath The list of path strings making up the (initial) class
+     *      path of this class loader. The strings may contain globbing
+     *      characters which will be resolved to build the actual class path.
+     */
+    public void reconfigure(String[] classPath) {
+        if (log.isDebugEnabled()) {
+            log.debug("reconfigure: Reconfiguring the with {}",
+                Arrays.asList(classPath));
+        }
+
+        // whether the loader is destroyed
+        if (isDestroyed()) {
+            log.warn("Cannot reconfigure this destroyed class loader");
+            return;
+        }
+
+        // assign new path and register
+        setPaths(classPath);
+        buildRepository();
+
+        dirty = !hasLoadedResources();
+        log.debug("reconfigure: Class loader is dirty now: {}", (isDirty()
+                ? "yes"
+                : "no"));
+    }
+
+    //---------- RepositoryClassLoader overwrites -----------------------------
+
+    /**
+     * Calls the base class implementation to actually retrieve the resource.
+     * If the resource could be found and provides a non-<code>null</code>
+     * {@link ClassLoaderResource#getExpiryProperty() expiry property}, the
+     * resource is registered with an internal cache to check with when
+     * a repository modification is observed in {@link #onEvent(EventIterator)}.
+     *
+     * @param name The name of the resource to be found
+     *
+     * @return the {@link ClassLoaderResource} found for the name or
+     *      <code>null</code> if no such resource is available in the class
+     *      path.
+     *
+     * @throws NullPointerException If this class loader has already been
+     *      destroyed.
+     */
+    /* package */ ClassLoaderResource findClassLoaderResource(String name) {
+        // call the base class implementation to actually search for it
+        ClassLoaderResource res = super.findClassLoaderResource(name);
+
+        // if it could be found, we register it with the caches
+        if (res != null) {
+            // register the resource in the expiry map, if an appropriate
+            // property is available
+            Property prop = res.getExpiryProperty();
+            if (prop != null) {
+                try {
+                    modTimeCache.put(prop.getPath(), res);
+                } catch (RepositoryException re) {
+                    log.warn("Cannot register the resource " + res +
+                        " for expiry", re);
+                }
+            }
+        }
+
+        // and finally return the resource
+        return res;
+    }
+
+    /**
+     * Builds the repository list from the list of path patterns and appends
+     * the path entries from any added handles. This method may be used multiple
+     * times, each time replacing the currently defined repository list.
+     *
+     * @throws NullPointerException If this class loader has already been
+     *      destroyed.
+     */
+    protected synchronized void buildRepository() {
+        super.buildRepository();
+
+        // add added repositories
+        ClassPathEntry[] addedPath = getAddedRepositories();
+        if (addedPath != null && addedPath.length > 0) {
+            ClassPathEntry[] oldClassPath = getRepository();
+            ClassPathEntry[] newClassPath =
+                new ClassPathEntry[oldClassPath.length + addedPath.length];
+
+            System.arraycopy(oldClassPath, 0, newClassPath, 0,
+                oldClassPath.length);
+            System.arraycopy(addedPath, 0, newClassPath, oldClassPath.length,
+                addedPath.length);
+
+            setRepository(newClassPath);
+        }
+    }
+
+    //---------- ModificationListener interface -------------------------------
+
+    /**
+     * Handles a repository item modifcation events checking whether a class
+     * needs to be expired. As a side effect, this method sets the class loader
+     * dirty if a loaded class has been modified in the repository.
+     *
+     * @param events The iterator of repository events to be handled.
+     */
+    public void onEvent(EventIterator events) {
+        while (events.hasNext()) {
+            Event event = events.nextEvent();
+            String path;
+            try {
+                path = event.getPath();
+            } catch (RepositoryException re) {
+                log.warn("onEvent: Cannot get path of event, ignoring", re);
+                continue;
+            }
+
+            log.debug(
+                "onEvent: Item {} has been modified, checking with cache", path);
+
+            ClassLoaderResource resource = (ClassLoaderResource) modTimeCache.get(path);
+            if (resource != null) {
+                log.debug("pageModified: Expiring cache entry {}", resource);
+                expireResource(resource);
+            } else {
+                // might be in not-found cache - remove from there
+                if (event.getType() == Event.NODE_ADDED
+                    || event.getType() == Event.PROPERTY_ADDED) {
+                    log.debug("pageModified: Clearing not-found cache for possible new class");
+                    cleanCache();
+                }
+            }
+
+        }
+    }
+
+    //----------- Object overwrite ---------------------------------------------
+
+    /**
+     * Returns a string representation of this class loader.
+     */
+    public String toString() {
+        if (isDestroyed()) {
+            return super.toString();
+        }
+
+        StringBuilder buf = new StringBuilder(super.toString());
+        buf.append(", dirty: ");
+        buf.append(isDirty());
+        return buf.toString();
+    }
+
+    //---------- internal ------------------------------------------------------
+
+    /**
+     * Sets the list of class path entries to add to the class path after
+     * reconfiguration or reinstantiation.
+     *
+     * @param addedRepositories The list of class path entries to keep for
+     *      readdition.
+     */
+    protected void setAddedRepositories(ClassPathEntry[] addedRepositories) {
+        this.addedRepositories = addedRepositories;
+    }
+
+    /**
+     * Returns the list of added class path entries to readd them to the class
+     * path after reconfiguring the class loader.
+     */
+    protected ClassPathEntry[] getAddedRepositories() {
+        return addedRepositories;
+    }
+
+    /**
+     * Adds the class path entry to the current class path list. If the class
+     * loader has already been destroyed, this method creates a single entry
+     * class path list with the new class path entry.
+     * <p>
+     * Besides adding the entry to the current class path, it is also added to
+     * the list to be readded after reconfiguration and/or reinstantiation.
+     *
+     * @see #getAddedRepositories()
+     * @see #setAddedRepositories(ClassPathEntry[])
+     */
+    protected void addClassPathEntry(ClassPathEntry cpe) {
+        super.addClassPathEntry(cpe);
+
+        // add the repsitory to the list of added repositories
+        ClassPathEntry[] oldClassPath = getAddedRepositories();
+        ClassPathEntry[] newClassPath = addClassPathEntry(oldClassPath, cpe);
+        setAddedRepositories(newClassPath);
+    }
+
+    /**
+     * Registers this class loader with the observation service to get
+     * information on page updates in the class path and to the path
+     * pattern list to get class path updates.
+     *
+     * @throws NullPointerException if this class loader has already been
+     *      destroyed.
+     */
+    private final void registerModificationListener() {
+        log.debug("registerModificationListener: Registering to the observation service");
+
+        final String[] paths = this.getPaths();
+        this.proxyListeners = new EventListener[this.getPaths().length];
+        for(int i=0; i < paths.length; i++ ) {
+            final String path = paths[i];
+            try {
+                final EventListener listener = new ProxyEventListener(this);
+                final ObservationManager om = getSession().getWorkspace().getObservationManager();
+                om.addEventListener(listener, 255, path, true, null, null, false);
+                proxyListeners[i] = listener;
+            } catch (RepositoryException re) {
+                log.error("registerModificationListener: Cannot register " +
+                    this + " with observation manager", re);
+            }
+        }
+    }
+
+    /**
+     * Removes this instances registrations from the observation service and
+     * the path pattern list.
+     *
+     * @throws NullPointerException if this class loader has already been
+     *      destroyed.
+     */
+    private final void unregisterListener() {
+        log.debug("registerModificationListener: Deregistering from the observation service");
+        if ( this.proxyListeners != null ) {
+            for(final EventListener listener : this.proxyListeners) {
+                if ( listener != null ) {
+                    try {
+                        final ObservationManager om = getSession().getWorkspace().getObservationManager();
+                        om.removeEventListener(listener);
+                    } catch (RepositoryException re) {
+                        log.error("unregisterListener: Cannot unregister " +
+                            this + " from observation manager", re);
+                    }
+                }
+            }
+            this.proxyListeners = null;
+        }
+    }
+
+    /**
+     * Checks whether the page backing the resource has been updated with a
+     * version, such that this new version would be used to access the resource.
+     * In this case the resource has expired and the class loader needs to be
+     * set dirty.
+     *
+     * @param resource The <code>ClassLoaderResource</code> to check for
+     *      expiry.
+     */
+    private boolean expireResource(ClassLoaderResource resource) {
+
+        // check whether the resource is expired (only if a class has been loaded)
+        boolean exp = resource.getLoadedClass() != null && resource.isExpired();
+
+        // update dirty flag accordingly
+        dirty |= exp;
+        log.debug("expireResource: Loader dirty: {}", new Boolean(isDirty()));
+
+        // return the expiry status
+        return exp;
+    }
+
+    /**
+     * Returns the list of classpath entries after resetting each of them.
+     *
+     * @param list The list of {@link ClassPathEntry}s to reset
+     *
+     * @return The list of reset {@link ClassPathEntry}s.
+     */
+    private ClassPathEntry[] resetClassPathEntries(
+            ClassPathEntry[] oldClassPath) {
+        if (oldClassPath != null) {
+            for (int i=0; i < oldClassPath.length; i++) {
+                ClassPathEntry entry = oldClassPath[i];
+                log.debug("resetClassPathEntries: Cloning {}", entry);
+                oldClassPath[i] = entry.copy();
+            }
+        } else {
+            log.debug("resetClassPathEntries: No list to reset");
+        }
+        return oldClassPath;
+    }
+
+    protected final static class ProxyEventListener implements EventListener {
+
+        private final EventListener delegatee;
+
+        public ProxyEventListener(final EventListener delegatee) {
+            this.delegatee = delegatee;
+        }
+        /**
+         * @see javax.jcr.observation.EventListener#onEvent(javax.jcr.observation.EventIterator)
+         */
+        public void onEvent(EventIterator events) {
+            this.delegatee.onEvent(events);
+        }
+    }
+}
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/RepositoryClassLoaderFacade.java b/src/main/java/org/apache/sling/jcr/classloader/internal/RepositoryClassLoaderFacade.java
index f33a834..d52ee8f 100644
--- a/src/main/java/org/apache/sling/jcr/classloader/internal/RepositoryClassLoaderFacade.java
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/RepositoryClassLoaderFacade.java
@@ -25,7 +25,6 @@ import java.util.Enumeration;
 
 import javax.jcr.RepositoryException;
 
-import org.apache.jackrabbit.classloader.DynamicRepositoryClassLoader;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/URLRepositoryClassLoader.java b/src/main/java/org/apache/sling/jcr/classloader/internal/URLRepositoryClassLoader.java
new file mode 100644
index 0000000..7755fd9
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/URLRepositoryClassLoader.java
@@ -0,0 +1,795 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal;
+
+import java.beans.Introspector;
+import java.io.IOException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.security.AccessController;
+import java.security.PrivilegedExceptionAction;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Date;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.jar.Attributes;
+import java.util.jar.Manifest;
+
+import javax.jcr.RepositoryException;
+import javax.jcr.Session;
+
+import org.apache.sling.jcr.classloader.internal.net.JCRURLConnection;
+import org.apache.sling.jcr.classloader.internal.net.URLFactory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+
+/**
+ * The <code>RepositoryClassLoader</code> class extends the
+ * <code>URLClassLoader</code> and provides the functionality to load classes
+ * and resources from JCR Repository.
+ * <p>
+ * This class loader supports loading classes from the Repository hierarchy,
+ * such as a <em>classes</em> 'folder', but also from Jar and Zip files stored
+ * in the Repository.
+ * <p>
+ * For enhanced performance, this class loader keeps a list of resources and
+ * classes which have already been loaded through this class loader. If later
+ * requests ask for already cached resources, these are returned without
+ * checking whether the underlying repository actually still exists.
+ * <p>
+ */
+public class URLRepositoryClassLoader extends URLClassLoader {
+
+    /** default log category */
+    private final Logger log =
+        LoggerFactory.getLogger(this.getClass().getName());
+
+    /** An empty list of url paths to call superclass constructor */
+    private static final URL[] NULL_PATH = {};
+
+    /**
+     * The special resource representing a resource which could not be
+     * found in the class path.
+     *
+     * @see #cache
+     * @see #findClassLoaderResource(String)
+     */
+    /* package */ static final ClassLoaderResource NOT_FOUND_RESOURCE =
+        new ClassLoaderResource(null, "[sentinel]", null) {
+            public boolean isExpired() {
+                return false;
+            }
+        };
+
+    /**
+     * The classpath which this classloader searches for class definitions.
+     * Each element of the vector should be either a directory, a .zip
+     * file, or a .jar file.
+     * <p>
+     * It may be empty when only system classes are controlled.
+     */
+    private ClassPathEntry[] repository;
+
+    /**
+     * The list of paths to use as a classpath.
+     */
+    private String[] paths;
+
+    /**
+     * The <code>Session</code> grants access to the Repository to access the
+     * resources.
+     * <p>
+     * This field is not final such that it may be cleared when the class loader
+     * is destroyed.
+     */
+    private Session session;
+
+    /**
+     * Cache of resources found or not found in the class path. The map is
+     * indexed by resource name and contains mappings to instances of the
+     * {@link ClassLoaderResource} class. If a resource has been tried to be
+     * loaded, which could not be found, the resource is cached with the
+     * special mapping to {@link #NOT_FOUND_RESOURCE}.
+     *
+     * @see #NOT_FOUND_RESOURCE
+     * @see #findClassLoaderResource(String)
+     */
+    private Map<String, ClassLoaderResource> cache;
+
+    /**
+     * Flag indicating whether the {@link #destroy()} method has already been
+     * called (<code>true</code>) or not (<code>false</code>)
+     */
+    private boolean destroyed;
+
+    /**
+     * Creates a <code>RepositoryClassLoader</code> from a list of item path
+     * strings containing globbing pattens for the paths defining the class
+     * path.
+     *
+     * @param session The <code>Session</code> to use to access the class items.
+     * @param classPath The list of path strings making up the (initial) class
+     *      path of this class loader. The strings may contain globbing
+     *      characters which will be resolved to build the actual class path.
+     * @param parent The parent <code>ClassLoader</code>, which may be
+     *            <code>null</code>.
+     *
+     * @throws NullPointerException if either the session or the handles list is
+     *             <code>null</code>.
+     */
+    public URLRepositoryClassLoader(Session session, String[] classPath,
+        ClassLoader parent) {
+        // initialize the super class with an empty class path
+        super(NULL_PATH, parent);
+
+        // check session and handles
+        if (session == null) {
+            throw new NullPointerException("session");
+        }
+        if (classPath == null || classPath.length == 0) {
+            throw new NullPointerException("handles");
+        }
+
+        // set fields
+        this.session = session;
+        setPaths(classPath);
+        this.cache = new HashMap<String, ClassLoaderResource>();
+        this.destroyed = false;
+
+        // build the class repositories list
+        buildRepository();
+
+        log.debug("RepositoryClassLoader: {} ready", this);
+    }
+
+    /**
+     * Returns <code>true</code> if this class loader has already been destroyed
+     * by calling {@link #destroy()}.
+     */
+    protected boolean isDestroyed() {
+        return destroyed;
+    }
+
+    protected String[] getPaths() {
+        return this.paths;
+    }
+
+    protected void setPaths(final String[] classPath) {
+        this.paths = classPath;
+    }
+
+    /**
+     * Destroys this class loader. This process encompasses all steps needed
+     * to remove as much references to this class loader as possible.
+     * <p>
+     * <em>NOTE</em>: This method just clears all internal fields and especially
+     * the class path to render this class loader unusable.
+     * <p>
+     * This implementation does not throw any exceptions.
+     */
+    public void destroy() {
+        // we expect to be called only once, so we stop destroyal here
+        if (isDestroyed()) {
+            log.debug("Instance is already destroyed");
+            return;
+        }
+
+        // set destroyal guard
+        destroyed = true;
+
+        // clear caches and references
+        setRepository(null);
+        setPaths(null);
+        session = null;
+
+        // clear the cache of loaded resources and flush cached class
+        // introspections of the JavaBean framework
+        if (cache != null) {
+            final Iterator<ClassLoaderResource> ci = cache.values().iterator();
+            while ( ci.hasNext() ) {
+                final ClassLoaderResource res = ci.next();
+                if (res.getLoadedClass() != null) {
+                    Introspector.flushFromCaches(res.getLoadedClass());
+                    res.setLoadedClass(null);
+                }
+            }
+            cache.clear();
+        }
+    }
+
+    //---------- URLClassLoader overwrites -------------------------------------
+
+    /**
+     * Finds and loads the class with the specified name from the class path.
+     *
+     * @param name the name of the class
+     * @return the resulting class
+     *
+     * @throws ClassNotFoundException If the named class could not be found or
+     *      if this class loader has already been destroyed.
+     */
+    protected Class findClass(final String name) throws ClassNotFoundException {
+
+        if (isDestroyed()) {
+            throw new ClassNotFoundException(name + " (Classloader destroyed)");
+        }
+
+        log.debug("findClass: Try to find class {}", name);
+
+        try {
+            return (Class) AccessController
+                .doPrivileged(new PrivilegedExceptionAction() {
+
+                    public Object run() throws ClassNotFoundException {
+                        return findClassPrivileged(name);
+                    }
+                });
+        } catch (java.security.PrivilegedActionException pae) {
+            throw (ClassNotFoundException) pae.getException();
+        }
+    }
+
+    /**
+     * Finds the resource with the specified name on the search path.
+     *
+     * @param name the name of the resource
+     *
+     * @return a <code>URL</code> for the resource, or <code>null</code>
+     *      if the resource could not be found or if the class loader has
+     *      already been destroyed.
+     */
+    public URL findResource(String name) {
+
+        if (isDestroyed()) {
+            log.warn("Destroyed class loader cannot find a resource");
+            return null;
+        }
+
+        log.debug("findResource: Try to find resource {}", name);
+
+        ClassLoaderResource res = findClassLoaderResource(name);
+        if (res != null) {
+            log.debug("findResource: Getting resource from {}, created {}",
+                res, new Date(res.getLastModificationTime()));
+            return res.getURL();
+        }
+
+        return null;
+    }
+
+    /**
+     * Returns an Enumeration of URLs representing all of the resources
+     * on the search path having the specified name.
+     *
+     * @param name the resource name
+     *
+     * @return an <code>Enumeration</code> of <code>URL</code>s. This is an
+     *      empty enumeration if no resources are found by this class loader
+     *      or if this class loader has already been destroyed.
+     */
+    public Enumeration findResources(String name) {
+
+        if (isDestroyed()) {
+            log.warn("Destroyed class loader cannot find resources");
+            return new Enumeration() {
+                public boolean hasMoreElements() {
+                    return false;
+                }
+                public Object nextElement() {
+                    throw new NoSuchElementException("No Entries");
+                }
+            };
+        }
+
+        log.debug("findResources: Try to find resources for {}", name);
+
+        List list = new LinkedList();
+        for (int i=0; i < repository.length; i++) {
+            final ClassPathEntry cp = repository[i];
+            log.debug("findResources: Trying {}", cp);
+
+            ClassLoaderResource res = cp.getResource(name);
+            if (res != null) {
+                log.debug("findResources: Adding resource from {}, created {}",
+                    res, new Date(res.getLastModificationTime()));
+                URL url = res.getURL();
+                if (url != null) {
+                    list.add(url);
+                }
+            }
+
+        }
+
+        // return the enumeration on the list
+        return Collections.enumeration(list);
+    }
+
+    /**
+     * Returns the search path of URLs for loading classes and resources.
+     * This includes the original list of URLs specified to the constructor,
+     * along with any URLs subsequently appended by the {@link #addURL(URL)}
+     * and {@link #addHandle(String)} methods.
+     *
+     * @return the search path of URLs for loading classes and resources. The
+     *      list is empty, if this class loader has already been destroyed.
+     * @see java.net.URLClassLoader#getURLs()
+     */
+    public URL[] getURLs() {
+        if (isDestroyed()) {
+            log.warn("Destroyed class loader has no URLs any more");
+            return new URL[0];
+        }
+
+        List urls = new ArrayList();
+        for (int i=0; i < repository.length; i++) {
+            URL url = repository[i].toURL();
+            if (url != null) {
+                urls.add(url);
+            }
+        }
+        return (URL[]) urls.toArray(new URL[urls.size()]);
+    }
+
+    /**
+     * Appends the specified URL to the list of URLs to search for
+     * classes and resources. Only Repository URLs with the protocol set to
+     * <code>JCR</code> are considered for addition. The system will find out
+     * whether the URL points to a directory or a jar archive.
+     * <p>
+     * URLs added using this method will be preserved through reconfiguration
+     * and reinstantiation.
+     * <p>
+     * If this class loader has already been destroyed this method has no
+     * effect.
+     *
+     * @param url the <code>JCR</code> URL to be added to the search path of
+     *      URLs.
+     * @see java.net.URLClassLoader#addURL(java.net.URL)
+     */
+    protected void addURL(URL url) {
+        if (isDestroyed()) {
+            log.warn("Cannot add URL to destroyed class loader");
+
+        } else if (checkURL(url)) {
+            // Repository URL
+            log.debug("addURL: Adding URL {}", url);
+            try {
+                JCRURLConnection conn = (JCRURLConnection) url.openConnection();
+                ClassPathEntry cp = ClassPathEntry.getInstance(
+                    conn.getSession(), conn.getPath());
+                addClassPathEntry(cp);
+            } catch (IOException ioe) {
+                log.warn("addURL: Cannot add URL " + url, ioe);
+            }
+
+        } else {
+            log.warn("addURL: {} is not a Repository URL, ignored", url);
+        }
+    }
+
+    //---------- Property access ----------------------------------------------
+
+    /**
+     * Returns the named {@link ClassLoaderResource} if it is contained in the
+     * cache. If the resource does not exist in the cache or has not been found
+     * in the class path at an earlier point in time, <code>null</code> is
+     * returned.
+     *
+     * @param name The name of the resource to retrieve from the cache.
+     *
+     * @return The named <code>ClassLoaderResource</code> or <code>null</code>
+     *      if not loaded.
+     *
+     * @throws NullPointerException If this class loader has already been
+     *      destroyed.
+     */
+    /* package */ ClassLoaderResource getCachedResource(String name) {
+        Object res = cache.get(name);
+        if (res == null || res == NOT_FOUND_RESOURCE) {
+            log.debug("Resource {} not cached", name);
+            return null;
+        }
+
+        return (ClassLoaderResource) res;
+    }
+
+    /**
+     * Returns an <code>Iterator</code> on all resources in the cache. This
+     * iterator may also contain {@link #NOT_FOUND_RESOURCE sentinel} entries
+     * for resources, which failed to load. Callers of this method should take
+     * care to filter out such resources before acting on it.
+     *
+     * @throws NullPointerException If this class loader has already been
+     *      destroyed.
+     */
+    /* package */ Iterator getCachedResources() {
+        return cache.values().iterator();
+    }
+
+    /**
+     * Removes all entries from the cache of loaded resources, which mark
+     * resources, which have not been found as of yet.
+     *
+     * @throws NullPointerException If this class loader has already been
+     *      destroyed.
+     */
+    protected void cleanCache() {
+        final Iterator<ClassLoaderResource> ci = this.cache.values().iterator();
+        while (ci.hasNext()) {
+            if (ci.next() == NOT_FOUND_RESOURCE) {
+                ci.remove();
+            }
+        }
+    }
+
+    /**
+     * Returns <code>true</code>, if the cache is not empty. If the
+     * {@link #cleanCache()} method is not called before calling this method, a
+     * false positive result may be returned.
+     *
+     * @throws NullPointerException If this class loader has already been
+     *      destroyed.
+     */
+    protected boolean hasLoadedResources() {
+        return cache.isEmpty();
+    }
+
+    /**
+     * Returns the session used by this class loader to access the repository.
+     * If this class loader has already been destroyed, this <code>null</code>
+     * is returned.
+     */
+    protected Session getSession() {
+        return session;
+    }
+
+    /**
+     * Sets the current active class path to the list of class path entries.
+     */
+    protected void setRepository(ClassPathEntry[] classPath) {
+        this.repository = classPath;
+    }
+
+    /**
+     * Returns the current active class path entries list or <code>null</code>
+     * if this class loader has already been destroyed.
+     */
+    protected ClassPathEntry[] getRepository() {
+        return repository;
+    }
+
+    /**
+     * Adds the class path entry to the current class path list. If the class
+     * loader has already been destroyed, this method creates a single entry
+     * class path list with the new class path entry.
+     */
+    protected void addClassPathEntry(ClassPathEntry cpe) {
+        log.debug("addHandle: Adding path {}", cpe.getPath());
+
+        // append the entry to the current class path
+        ClassPathEntry[] oldClassPath = getRepository();
+        ClassPathEntry[] newClassPath = addClassPathEntry(oldClassPath, cpe);
+        setRepository(newClassPath);
+    }
+
+    /**
+     * Helper method for class path handling to a new entry to an existing
+     * list and return the new list.
+     * <p>
+     * If <code>list</code> is <code>null</code> a new array is returned with
+     * a single element <code>newEntry</code>. Otherwise the array returned
+     * contains all elements of <code>list</code> and <code>newEntry</code>
+     * at the last position.
+     *
+     * @param list The array of class path entries, to which a new entry is
+     *      to be appended. This may be <code>null</code>.
+     * @param newEntry The new entry to append to the class path list.
+     *
+     * @return The extended class path list.
+     */
+    protected ClassPathEntry[] addClassPathEntry(ClassPathEntry[] list,
+            ClassPathEntry newEntry) {
+
+        // quickly define single entry array for the first entry
+        if (list == null) {
+            return new ClassPathEntry[]{ newEntry };
+        }
+
+        // create new array and copy old and new contents
+        ClassPathEntry[] newList = new ClassPathEntry[list.length+1];
+        System.arraycopy(list, 0, newList, 0, list.length);
+        newList[list.length] = newEntry;
+        return newList;
+    }
+
+    //---------- Object overwrite ---------------------------------------------
+
+    /**
+     * Returns a string representation of this instance.
+     */
+    public String toString() {
+        StringBuilder buf = new StringBuilder(getClass().getName());
+
+        if (isDestroyed()) {
+            buf.append(" - destroyed");
+        } else {
+            buf.append(": parent: { ");
+            buf.append(getParent());
+            buf.append(" }, user: ");
+            buf.append(session.getUserID());
+        }
+
+        return buf.toString();
+    }
+
+    //---------- internal ------------------------------------------------------
+
+    /**
+     * Builds the repository list from the list of path patterns and appends
+     * the path entries from any added handles. This method may be used multiple
+     * times, each time replacing the currently defined repository list.
+     *
+     * @throws NullPointerException If this class loader has already been
+     *      destroyed.
+     */
+    protected synchronized void buildRepository() {
+        List<ClassPathEntry> newRepository = new ArrayList<ClassPathEntry>(paths.length);
+
+        // build repository from path patterns
+        for (int i=0; i < paths.length; i++) {
+            final String entry = paths[i];
+            ClassPathEntry cp = null;
+
+            // try to find repository based on this path
+            if (repository != null) {
+                for (int j=0; j < repository.length; j++) {
+                    final ClassPathEntry tmp = repository[i];
+                    if (tmp.getPath().equals(entry)) {
+                        cp = tmp;
+                        break;
+                    }
+                }
+            }
+
+            // not found, creating new one
+            if (cp == null) {
+                cp = ClassPathEntry.getInstance(session, entry);
+            }
+
+            if (cp != null) {
+                log.debug("Adding path {}", entry);
+                newRepository.add(cp);
+            } else {
+                log.debug("Cannot get a ClassPathEntry for {}", entry);
+            }
+        }
+
+        // replace old repository with new one
+        final ClassPathEntry[] newClassPath = new ClassPathEntry[newRepository.size()];
+        newRepository.toArray(newClassPath);
+        setRepository(newClassPath);
+
+        // clear un-found resource cache
+        cleanCache();
+    }
+
+    /**
+     * Tries to find the class in the class path from within a
+     * <code>PrivilegedAction</code>. Throws <code>ClassNotFoundException</code>
+     * if no class can be found for the name.
+     *
+     * @param name the name of the class
+     *
+     * @return the resulting class
+     *
+     * @throws ClassNotFoundException if the class could not be found
+     * @throws NullPointerException If this class loader has already been
+     *      destroyed.
+     */
+    private Class findClassPrivileged(String name) throws ClassNotFoundException {
+
+        // prepare the name of the class
+        final String path = name.replace('.', '/').concat(".class");
+        log.debug("findClassPrivileged: Try to find path {} for class {}",
+            path, name);
+
+        ClassLoaderResource res = findClassLoaderResource(path);
+        if (res != null) {
+
+             // try defining the class, error aborts
+             try {
+                 log.debug(
+                    "findClassPrivileged: Loading class from {}, created {}",
+                    res, new Date(res.getLastModificationTime()));
+
+                 Class c = defineClass(name, res);
+                 if (c == null) {
+                     log.warn("defineClass returned null for class {}", name);
+                     throw new ClassNotFoundException(name);
+                 }
+                 return c;
+
+             } catch (IOException ioe) {
+                 log.debug("defineClass failed", ioe);
+                 throw new ClassNotFoundException(name, ioe);
+             } catch (Throwable t) {
+                 log.debug("defineClass failed", t);
+                 throw new ClassNotFoundException(name, t);
+             }
+         }
+
+        throw new ClassNotFoundException(name);
+     }
+
+    /**
+     * Returns a {@link ClassLoaderResource} for the given <code>name</code> or
+     * <code>null</code> if not existing. If the resource has already been
+     * loaded earlier, the cached instance is returned. If the resource has
+     * not been found in an earlier call to this method, <code>null</code> is
+     * returned. Otherwise the resource is looked up in the class path. If
+     * found, the resource is cached and returned. If not found, the
+     * {@link #NOT_FOUND_RESOURCE} is cached for the name and <code>null</code>
+     * is returned.
+     *
+     * @param name The name of the resource to return.
+     *
+     * @return The named <code>ClassLoaderResource</code> if found or
+     *      <code>null</code> if not found.
+     *
+     * @throws NullPointerException If this class loader has already been
+     *      destroyed.
+     */
+    /* package */ ClassLoaderResource findClassLoaderResource(String name) {
+
+        // check for cached resources first
+        ClassLoaderResource res = cache.get(name);
+        if (res == NOT_FOUND_RESOURCE) {
+            log.debug("Resource '{}' known to not exist in class path", name);
+            return null;
+        } else if (res != null) {
+            return res;
+        }
+
+        // walk the repository list and try to find the resource
+        for (int i = 0; i < repository.length; i++) {
+            final ClassPathEntry cp = repository[i];
+            log.debug("Checking {}", cp);
+
+            res = cp.getResource(name);
+            if (res != null) {
+                log.debug("Found resource in {}, created ", res, new Date(
+                    res.getLastModificationTime()));
+                cache.put(name, res);
+                return res;
+            }
+
+        }
+
+        log.debug("No classpath entry contains {}", name);
+        cache.put(name, NOT_FOUND_RESOURCE);
+        return null;
+    }
+
+    /**
+     * Defines a class getting the bytes for the class from the resource
+     *
+     * @param name The fully qualified class name
+     * @param res The resource to obtain the class bytes from
+     *
+     * @throws RepositoryException If a problem occurrs getting at the data.
+     * @throws IOException If a problem occurrs reading the class bytes from
+     *      the resource.
+     * @throws ClassFormatError If the class bytes read from the resource are
+     *      not a valid class.
+     */
+    private Class defineClass(String name, ClassLoaderResource res)
+            throws IOException, RepositoryException {
+
+        log.debug("defineClass({}, {})", name, res);
+
+        Class clazz = res.getLoadedClass();
+        if (clazz == null) {
+
+            /**
+             * This following code for packages is duplicate from URLClassLoader
+             * because it is private there. I would like to not be forced to
+             * do this, but I still have to find a way ... -fmeschbe
+             */
+
+            // package support
+            int i = name.lastIndexOf('.');
+            if (i != -1) {
+                String pkgname = name.substring(0, i);
+                // Check if package already loaded.
+                Package pkg = getPackage(pkgname);
+                URL url = res.getCodeSourceURL();
+                Manifest man = res.getManifest();
+                if (pkg != null) {
+                    // Package found, so check package sealing.
+                    boolean ok;
+                    if (pkg.isSealed()) {
+                        // Verify that code source URL is the same.
+                        ok = pkg.isSealed(url);
+                    } else {
+                        // Make sure we are not attempting to seal the package
+                        // at this code source URL.
+                        ok = (man == null) || !isSealed(pkgname, man);
+                    }
+                    if (!ok) {
+                        throw new SecurityException("sealing violation");
+                    }
+                } else {
+                    if (man != null) {
+                        definePackage(pkgname, man, url);
+                    } else {
+                        definePackage(pkgname, null, null, null, null, null, null, null);
+                    }
+                }
+            }
+
+            byte[] data = res.getBytes();
+            clazz = defineClass(name, data, 0, data.length);
+            res.setLoadedClass(clazz);
+        }
+
+        return clazz;
+    }
+
+    /**
+     * Returns true if the specified package name is sealed according to the
+     * given manifest
+     * <p>
+     * This code is duplicate from <code>URLClassLoader.isSealed</code> because
+     * the latter has private access and we need the method here.
+     */
+    private boolean isSealed(String name, Manifest man) {
+         String path = name.replace('.', '/').concat("/");
+         Attributes attr = man.getAttributes(path);
+         String sealed = null;
+         if (attr != null) {
+             sealed = attr.getValue(Attributes.Name.SEALED);
+         }
+         if (sealed == null) {
+             if ((attr = man.getMainAttributes()) != null) {
+                 sealed = attr.getValue(Attributes.Name.SEALED);
+             }
+         }
+         return "true".equalsIgnoreCase(sealed);
+    }
+
+    /**
+     * Returns <code>true</code> if the <code>url</code> is a <code>JCR</code>
+     * URL.
+     *
+     * @param url The URL to check whether it is a valid <code>JCR</code> URL.
+     *
+     * @return <code>true</code> if <code>url</code> is a valid <code>JCR</code>
+     *      URL.
+     *
+     * @throws NullPointerException if <code>url</code> is <code>null</code>.
+     */
+    private boolean checkURL(URL url) {
+        return URLFactory.REPOSITORY_SCHEME.equalsIgnoreCase(url.getProtocol());
+    }
+}
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/Util.java b/src/main/java/org/apache/sling/jcr/classloader/internal/Util.java
new file mode 100644
index 0000000..01e41f8
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/Util.java
@@ -0,0 +1,166 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal;
+
+import javax.jcr.AccessDeniedException;
+import javax.jcr.Item;
+import javax.jcr.ItemNotFoundException;
+import javax.jcr.Node;
+import javax.jcr.PathNotFoundException;
+import javax.jcr.Property;
+import javax.jcr.PropertyType;
+import javax.jcr.RepositoryException;
+import javax.jcr.ValueFormatException;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * The <code>Util</code> provides helper methods for the repository
+ * classloader and its class path entry and resource classes.
+ * <p>
+ * This class may not be extended or instantiated, it just contains static
+ * utility methods.
+ */
+public class Util {
+
+    /** default logging */
+    private static final Logger log = LoggerFactory.getLogger(Util.class);
+
+    /** Private constructor to not instantiate */
+    private Util() {
+    }
+
+    /**
+     * Resolves the given <code>item</code> to a <code>Property</code> from
+     * which contents can be read.
+     * <p>
+     * The following mechanism is used to derive the contents:
+     * <ol>
+     * <li>If the <code>item</code> is a property, this property is used</li>
+     * <li>If the <code>item</code> is a node, three steps are tested:
+     * <ol>
+     * <li>If the node has a <code>jcr:content</code> child node, use that
+     * child node in the next steps. Otherwise continue with the node.</li>
+     * <li>Check for a <code>jcr:data</code> property and use that property
+     * if existing.</li>
+     * <li>Otherwise call <code>getPrimaryItem</code> method repeatedly until
+     * a property is returned or until no more primary item is available.</li>
+     * </ol>
+     * </ol>
+     * If no property can be resolved using the above algorithm or if the
+     * resulting property is a multivalue property, <code>null</code> is
+     * returned. Otherwise if the resulting property is a <code>REFERENCE</code>
+     * property, the node referred to is retrieved and this method is called
+     * recursively with the node. Otherwise, the resulting property is returned.
+     * 
+     * @param item The <code>Item</code> to resolve to a <code>Property</code>.
+     * @return The resolved <code>Property</code> or <code>null</code> if
+     *         the resolved property is a multi-valued property or the
+     *         <code>item</code> is a node which cannot be resolved to a data
+     *         property.
+     * @throws ValueFormatException If the <code>item</code> resolves to a
+     *             single-valued <code>REFERENCE</code> type property which
+     *             cannot be resolved to the node referred to.
+     * @throws RepositoryException if another error occurrs accessing the
+     *             repository.
+     */
+    public static Property getProperty(Item item) throws ValueFormatException,
+            RepositoryException {
+
+        Property prop;
+        if (item.isNode()) {
+
+            // check whether the node has a jcr:content node (e.g. nt:file)
+            Node node = (Node) item;
+            if (node.hasNode("jcr:content")) {
+                node = node.getNode("jcr:content");
+            }
+
+            // if the node has a jcr:data property, use that property
+            if (node.hasProperty("jcr:data")) {
+                
+                prop = node.getProperty("jcr:data");
+
+            } else {
+
+                // otherwise try to follow default item trail
+                try {
+                    item = node.getPrimaryItem();
+                    while (item.isNode()) {
+                        item = ((Node) item).getPrimaryItem();
+                    }
+                    prop = (Property) item;
+                } catch (ItemNotFoundException infe) {
+                    // we don't actually care, but log for completeness
+                    log.debug("getProperty: No primary items for "
+                        + node.getPath(), infe);
+                    return null;
+                }
+            }
+
+        } else {
+
+            prop = (Property) item;
+
+        }
+
+        // we get here with a property - otherwise an exception has already
+        // been thrown
+        if (prop.getDefinition().isMultiple()) {
+            log.error("{} is a multivalue property", prop.getPath());
+            return null;
+        } else if (prop.getType() == PropertyType.REFERENCE) {
+            Node node = prop.getNode();
+            log.info("Property {} refers to node {}; finding primary item",
+                prop.getPath(), node.getPath());
+            return getProperty(node);
+        }
+
+        return prop;
+    }
+
+    /**
+     * Returns the last modification time of the property, which is the long
+     * value of the <code>jcr:lastModified</code> property of the parent node
+     * of <code>prop</code>. If the parent node does not have a
+     * <code>jcr:lastModified</code> property the current system time is
+     * returned.
+     * 
+     * @param prop The property for which to return the last modification time.
+     * @return The last modification time of the resource or the current time if
+     *         the parent node of the property does not have a
+     *         <code>jcr:lastModified</code> property.
+     * @throws ItemNotFoundException If the parent node of the property cannot
+     *             be retrieved.
+     * @throws AccessDeniedException If (read) access to the parent node is
+     *             denied.
+     * @throws RepositoryException If any other error occurrs accessing the
+     *             repository to retrieve the last modification time.
+     */
+    public static long getLastModificationTime(Property prop)
+            throws ItemNotFoundException, PathNotFoundException,
+            AccessDeniedException, RepositoryException {
+
+        Node parent = prop.getParent();
+        if (parent.hasProperty("jcr:lastModified")) {
+            return parent.getProperty("jcr:lastModified").getLong();
+        }
+
+        return System.currentTimeMillis();
+    }
+}
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/net/FileParts.java b/src/main/java/org/apache/sling/jcr/classloader/internal/net/FileParts.java
new file mode 100644
index 0000000..a5057f3
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/net/FileParts.java
@@ -0,0 +1,312 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal.net;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
+import java.net.URLEncoder;
+
+import javax.jcr.Session;
+
+/**
+ * The <code>FileParts</code> class provides composing and parsing functionality
+ * to create and analize JCR Repository URL file components.
+ * <p>
+ * The file component of a JCR Repository URL has the format
+ * <pre>
+ *      file = [ "jcr:" [ "//" authority ] ] "/" repository "/" workspace jarpath .
+ *      authority = // URL authority specification
+ *      repository = // URL encoded repository name
+ *      workspace = // URL encoded workspace name
+ *      jarpath = path [ "!/" [ entry ] ] .
+ *      path = // The absolute item path (with a leading slash)
+ *      entry = // The (relative) path to the entry in an archive
+ * </pre>
+ * <p>
+ * To facitility use of this class with JCRJar URLs, the
+ * {@link #FileParts(String)} supports file specifications which contains
+ * the JCR Repository URL scheme name and an optional URL authority
+ * specification. This prefix in front of the real file specification is
+ * silently discarded. It is not included in the string representation returned
+ * by the {@link #toString()} method.
+ * <p>
+ * To make sure parsing is not complicated by implementation and use case
+ * specific repository and workspace names, those names are URL encoded using
+ * the <code>URLEncoder</code> class and <i>UTF-8</i> character encoding.
+ *
+ * @author Felix Meschberger
+ */
+class FileParts {
+
+    /** The decoded name of the repository */
+    private final String repository;
+
+    /** The decoded name of the workspace */
+    private final String workspace;
+
+    /** The repository item path part of the URL path */
+    private final String path;
+
+    /**
+     * The path to the entry in the archive, if the file spec contains the
+     * jar entry separator <i>!/</i>. If no entry path is specified, this is
+     * <code>null</code>. If no path is specified after the <i>!/</i> this
+     * is an empty string.
+     */
+    private final String entryPath;
+
+    /**
+     * Creates a new instance for the root node of the given session. The
+     * repository name is currently set to the fixed string "_" as there has not
+     * been established a repository naming convention yet. The name of the
+     * workspace is set to the name of the workspace to which the session is
+     * attached. The path is set to <code>"/"</code> to indicate the root node
+     * if the <code>path</code> argument is <code>null</code>.
+     *
+     * @param session The session for which to create this instance.
+     * @param path The absolute item path to initialize this instance with. If
+     *      <code>null</code> the item path is set to the <code>/</code>.
+     * @param entryPath The path to the archive entry to set on this instance.
+     *      This is expected to be a relative path without a leading slash and
+     *      may be <code>null</code>.
+     *
+     * @throws NullPointerException if <code>session</code> is
+     *      <code>null</code>.
+     */
+    FileParts(Session session, String path, String entryPath) {
+        this.repository = "_";
+        this.workspace = session.getWorkspace().getName();
+        this.path = (path == null) ? "/" : path;
+        this.entryPath = entryPath;
+    }
+
+    /**
+     * Creates an instance of this class setting the repository, workspace and
+     * path fields from the given <code>file</code> specification.
+     *
+     * @param file The specification providing the repository, workspace and
+     *      path values.
+     *
+     * @throws NullPointerException if <code>file</code> is
+     *      <code>null</code>.
+     * @throws IllegalArgumentException if <code>file</code> is not the
+     *      correct format.
+     */
+    FileParts(String file) {
+        if (!file.startsWith("/")) {
+            if (file.startsWith(URLFactory.REPOSITORY_SCHEME+":")) {
+                file = strip(file);
+            } else {
+                throw failure("Not an absolute file", file);
+            }
+        }
+
+        // find the repository name
+        int slash0 = 1;
+        int slash1 = file.indexOf('/', slash0);
+        if (slash1 < 0 || slash1-slash0 == 0) {
+            throw failure("Missing repository name", file);
+        }
+        this.repository = decode(file.substring(slash0, slash1));
+
+        // find the workspace name
+        slash0 = slash1 + 1;
+        slash1 = file.indexOf('/', slash0);
+        if (slash1 < 0 || slash1-slash0 == 0) {
+            throw failure("Missing workspace name", file);
+        }
+        this.workspace = decode(file.substring(slash0, slash1));
+
+        String fullPath = file.substring(slash1);
+        int bangSlash = JCRJarURLHandler.indexOfBangSlash(fullPath);
+        if (bangSlash < 0) {
+            this.path = fullPath;
+            this.entryPath = null;
+        } else {
+            this.path = fullPath.substring(0, bangSlash-1);
+            this.entryPath = fullPath.substring(bangSlash+1);
+        }
+    }
+
+    /**
+     * Returns the plain name of the repository.
+     */
+    String getRepository() {
+        return repository;
+    }
+
+    /**
+     * Returns the plain name of the workspace.
+     */
+    String getWorkspace() {
+        return workspace;
+    }
+
+    /**
+     * Returns the absolute repository path of the item.
+     */
+    String getPath() {
+        return path;
+    }
+
+    /**
+     * Returns the entry path of <code>null</code> if no entry exists.
+     */
+    String getEntryPath() {
+        return entryPath;
+    }
+
+    //---------- Object overwrites --------------------------------------------
+
+    /**
+     * Returns a hash code for this instance composed of the hash codes of the
+     * repository, workspace and path names.
+     */
+    public int hashCode() {
+        return getRepository().hashCode() +
+            17 * getWorkspace().hashCode() +
+            33 * getPath().hashCode();
+    }
+
+    /**
+     * Returns <code>true</code> if <code>obj</code> is the same as this or
+     * if other is a <code>FileParts</code> with the same path, workspace and
+     * repository. Otherwise <code>false</code> is returned.
+     */
+    public boolean equals(Object obj) {
+        if (obj == this) {
+            return true;
+        } else if (obj instanceof FileParts) {
+            FileParts other = (FileParts) obj;
+
+            // catch null entry path, fail if other has a defined entry path
+            if (getEntryPath() == null) {
+                if (other.getEntryPath() != null) {
+                    return false;
+                }
+            }
+
+            return getPath().equals(other.getPath()) &&
+                getWorkspace().equals(other.getWorkspace()) &&
+                getRepository().equals(other.getRepository()) &&
+                getEntryPath().equals(other.getEntryPath());
+        }
+
+        // fall back on null or other class
+        return false;
+    }
+
+    /**
+     * Returns the encoded string representation of this instance, which may
+     * later be fed to the {@link #FileParts(String)} constructor to recreate
+     * an equivalent instance.
+     */
+    public String toString() {
+        StringBuilder buf = new StringBuilder();
+        buf.append('/').append(encode(getRepository()));
+        buf.append('/').append(encode(getWorkspace()));
+        buf.append(getPath());
+
+        if (getEntryPath() != null) {
+            buf.append("!/").append(getEntryPath());
+        }
+
+        return buf.toString();
+    }
+
+    //---------- internal -----------------------------------------------------
+
+    /**
+     * @throws IllegalArgumentException If there is no path element after the
+     *      authority.
+     */
+    private String strip(String file) {
+        // cut off jcr: prefix - any other prefix, incl. double slash
+        // would cause an exception to be thrown in the constructor
+        int start = 4;
+
+        // check whether the remainder contains an authority specification
+        if (file.length() >= start+2 && file.charAt(start) == '/' &&
+                file.charAt(start+1) == '/') {
+
+            // find the slash after the authority, fail if missing
+            start = file.indexOf('/', start + 2);
+            if (start < 0) {
+                throw failure("Missing path after authority", file);
+            }
+        }
+
+        // return the file now
+        return file.substring(start);
+    }
+
+    /**
+     * Encodes the given string value using the <code>URLEncoder</code> and
+     * <i>UTF-8</i> character encoding.
+     *
+     * @param value The string value to encode.
+     *
+     * @return The encoded string value.
+     *
+     * @throws InternalError If <code>UTF-8</code> character set encoding is
+     *      not supported. As <code>UTF-8</code> is required to be implemented
+     *      on any Java platform, this error is not expected.
+     */
+    private String encode(String value) {
+        try {
+            return URLEncoder.encode(value, "UTF-8");
+        } catch (UnsupportedEncodingException e) {
+            // not expected, throw an InternalError
+            throw new InternalError("UTF-8 not supported");
+        }
+    }
+
+    /**
+     * Decodes the given string value using the <code>URLDecoder</code> and
+     * <i>UTF-8</i> character encoding.
+     *
+     * @param value The string value to decode.
+     *
+     * @return The decoded string value.
+     *
+     * @throws InternalError If <code>UTF-8</code> character set encoding is
+     *      not supported. As <code>UTF-8</code> is required to be implemented
+     *      on any Java platform, this error is not expected.
+     */
+    private String decode(String value) {
+        try {
+            return URLDecoder.decode(value, "UTF-8");
+        } catch (UnsupportedEncodingException e) {
+            // not expected, throw an InternalError
+            throw new InternalError("UTF-8 not supported");
+        }
+    }
+
+    /**
+     * Returns a <code>IllegalArgumentException</code> formatted with the
+     * given reason and causing file specification.
+     *
+     * @param reason The failure reason.
+     * @param file The original file specification leading to failure.
+     *
+     * @return A <code>IllegalArgumentException</code> with the given
+     *      reason and causing file specification.
+     */
+    private IllegalArgumentException failure(String reason, String file) {
+        return new IllegalArgumentException(reason + ": '" + file + "'");
+    }
+}
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRJarURLConnection.java b/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRJarURLConnection.java
new file mode 100644
index 0000000..29d4a20
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRJarURLConnection.java
@@ -0,0 +1,289 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal.net;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.jar.JarEntry;
+import java.util.jar.JarInputStream;
+
+import javax.jcr.Property;
+import javax.jcr.RepositoryException;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * The <code>JCRJarURLConnection</code> extends the
+ * {@link org.apache.sling.jcr.classloader.internal.net.JCRURLConnection} class to support accessing
+ * archive files stored in a JCR Repository.
+ * <p>
+ * Just like the base class, this class requires the URL to resolve, either
+ * directly or through primary item chain, to a repository <code>Property</code>.
+ * <p>
+ * Access to this connections property and archive entry content is perpared
+ * with the {@link #connect()}, which after calling the base class implementation
+ * to find the property tries to find the archive entry and set the connection's
+ * fields according to the entry. This implementation's {@link #connect()}
+ * method fails if the named entry does not exist in the archive.
+ * <p>
+ * The {@link #getInputStream()} method either returns an stream on the archive
+ * entry or on the archive depending on whether an entry path is specified
+ * in the URL or not. Like the base class implementation, this implementation
+ * returns a new <code>InputStream</code> on each invocation.
+ * <p>
+ * If an entry path is defined on the URL, the header fields are set from the
+ * archive entry:
+ * <table border="0" cellspacing="0" cellpadding="3">
+ *  <tr><td><code>Content-Type</code><td>Guessed from the entry name or
+ *      <code>application/octet-stream</code> if the type cannot be guessed
+ *      from the name</tr>
+ *  <tr><td><code>Content-Encoding</code><td><code>null</code></tr>
+ *  <tr><td><code>Content-Length</code><td>The size of the entry</tr>
+ *  <tr><td><code>Last-Modified</code><td>The last modification time of the
+ *      entry</tr>
+ * </table>
+ * <p>
+ * If no entry path is defined on the URL, the header fields are set from the
+ * property by the base class implementation with the exception of the
+ * content type, which is set to <code>application/java-archive</code> by
+ * the {@link #connect()} method.
+ * <p>
+ * <em>Note that this implementation does only support archives stored in the
+ * JCR Repository, no other contained storage such as </em>file<em> or
+ * </em>http<em> is supported.</em>
+ * <p>
+ * This class is not intended to be subclassed or instantiated by clients.
+ *
+ * @author Felix Meschberger
+ */
+public class JCRJarURLConnection extends JCRURLConnection {
+
+    /** default log category */
+    private static final Logger log =
+        LoggerFactory.getLogger(JCRJarURLConnection.class);
+
+    /**
+     * The name of the MIME content type for this connection's content if
+     * no entry path is defined on the URL (value is "application/java-archive").
+     */
+    protected static final String APPLICATION_JAR = "application/java-archive";
+
+    /**
+     * Creates an instance of this class for the given <code>url</code>
+     * supported by the <code>handler</code>.
+     *
+     * @param url The URL to base the connection on.
+     * @param handler The URL handler supporting the given URL.
+     */
+    JCRJarURLConnection(URL url, JCRJarURLHandler handler) {
+        super(url, handler);
+    }
+
+    /**
+     * Returns the path to the entry contained in the archive or
+     * <code>null</code> if the URL contains no entry specification in the
+     * path.
+     */
+    String getEntryPath() {
+        return getFileParts().getEntryPath();
+    }
+
+    /**
+     * Connects to the URL setting the header fields and preparing for the
+     * {@link #getProperty()} and {@link #getInputStream()} methods.
+     * <p>
+     * After calling the base class implemenation to get the basic connection,
+     * the entry is looked for in the archive to set the content type, content
+     * length and last modification time header fields according to the named
+     * entry. If no entry is defined on the URL, only the content type header
+     * field is set to <code>application/java-archive</code>.
+     * <p>
+     * When this method successfully returns, this connection is considered
+     * connected. In case of an exception thrown, the connection is not
+     * connected.
+     *
+     * @throws IOException if an error occurrs retrieving the data property or
+     *      any of the header field value properties or if any other errors
+     *      occurrs. Any cuasing exception is set as the cause of this
+     *      exception.
+     */
+    public synchronized void connect() throws IOException {
+
+        if (!connected) {
+
+            // have the base class connect to get the jar property
+            super.connect();
+
+            // we assume the connection is now (temporarily) connected,
+            // thus calling the getters will not result in a recursive loop
+            Property property = getProperty();
+            String contentType = getContentType();
+            String contentEncoding = getContentEncoding();
+            int contentLength = getContentLength();
+            long lastModified = getLastModified();
+
+            // mark as not connected to not get false positives if the
+            // following code fails
+            connected = false;
+
+            // Get hold of the data
+            try {
+
+                JarInputStream jins = null;
+                try {
+
+                    // try to get the jar input stream, fail if no jar
+                    jins = new JarInputStream(property.getStream());
+
+                    String entryPath = getEntryPath();
+                    if (entryPath != null) {
+
+                        JarEntry entry = findEntry(jins, entryPath);
+
+                        if (entry != null) {
+
+                            contentType = guessContentTypeFromName(entryPath);
+                            if (contentType == null) {
+                                contentType = APPLICATION_OCTET;
+                            }
+
+                            contentLength = (int) entry.getSize();
+                            lastModified = entry.getTime();
+
+                        } else {
+
+                            throw failure("connect", entryPath +
+                                " not contained in jar archive", null);
+
+                        }
+
+                    } else {
+
+                        // replaces the base class defined content type
+                        contentType = APPLICATION_JAR;
+
+                    }
+
+                } finally {
+                    if (jins != null) {
+                        try {
+                            jins.close();
+                        } catch (IOException ignore) {
+                        }
+                    }
+                }
+
+                log.debug("connect: Using atom '" + property.getPath()
+                    + "' with content type '" + contentType + "' for "
+                    + String.valueOf(contentLength) + " bytes");
+
+                // set the fields
+                setContentType(contentType);
+                setContentEncoding(contentEncoding);
+                setContentLength(contentLength);
+                setLastModified(lastModified);
+
+                // mark connection open
+                connected = true;
+
+            } catch (RepositoryException re) {
+
+                throw failure("connect", re.toString(), re);
+
+            }
+        }
+    }
+
+    /**
+     * Returns an input stream that reads from this open connection. If not
+     * entry path is specified in the URL, this method returns the input stream
+     * providing access to the archive as a whole. Otherwise the input stream
+     * returned is a <code>JarInputStream</code> positioned at the start of
+     * the named entry.
+     * <p>
+     * <b>NOTES:</b>
+     * <ul>
+     * <li>Each call to this method returns a new <code>InputStream</code>.
+     * <li>Do not forget to close the return stream when not used anymore for
+     *      the system to be able to free resources.
+     * </ul>
+     * <p>
+     * Calling this method implicitly calls {@link #connect()} to ensure the
+     * connection is open.
+     *
+     * @return The <code>InputStream</code> on the archive or the entry if
+     *      specified.
+     *
+     * @throws IOException if an error occurrs opening the connection through
+     *      {@link #connect()} or creating the <code>InputStream</code> on the
+     *      repository <code>Property</code>.
+     */
+    public InputStream getInputStream() throws IOException {
+
+        // get the input stream on the archive itself - also enforces connect()
+        InputStream ins = super.getInputStream();
+
+        // access the entry in the archive if defined
+        String entryPath = getEntryPath();
+        if (entryPath != null) {
+            // open the jar input stream
+            JarInputStream jins = new JarInputStream(ins);
+
+            // position at the correct entry
+            findEntry(jins, entryPath);
+
+            // return the input stream
+            return jins;
+        }
+
+        // otherwise just return the stream on the archive
+        return ins;
+    }
+
+    //----------- internal helper to find the entry ------------------------
+
+    /**
+     * Returns the <code>JarEntry</code> for the path from the
+     * <code>JarInputStream</code> or <code>null</code> if the path cannot
+     * be found in the archive.
+     *
+     * @param zins The <code>JarInputStream</code> to search in.
+     * @param path The path of the <code>JarEntry</code> to return.
+     *
+     * @return The <code>JarEntry</code> for the path or <code>null</code>
+     *      if no such entry can be found.
+     *
+     * @throws IOException if a problem occurrs reading from the stream.
+     */
+    static JarEntry findEntry(JarInputStream zins, String path)
+        throws IOException {
+
+        JarEntry entry = zins.getNextJarEntry();
+        while (entry != null) {
+            if (path.equals(entry.getName())) {
+                return entry;
+            }
+
+            entry = zins.getNextJarEntry();
+        }
+        // invariant : nothing found in the zip matching the path
+
+        return null;
+    }
+}
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRJarURLHandler.java b/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRJarURLHandler.java
new file mode 100644
index 0000000..39b7f26
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRJarURLHandler.java
@@ -0,0 +1,298 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal.net;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.net.URLConnection;
+
+import javax.jcr.Session;
+
+/**
+ * The <code>JCRJarURLHandler</code> is the <code>URLStreamHandler</code> for
+ * Java Archive URLs for archives from a JCR Repository URLs (JCRJar URL). The
+ * scheme for such ULRs will be <code>jar</code> while the file part of the URL
+ * has the scheme <code>jcr</code>.
+ * <p>
+ * JCRJar URLs have not been standardized yet and may only be created in the
+ * context of an existing <code>Session</code>. Therefore this handler is not
+ * globally available and JCR Repository URLs may only be created through the
+ * factory methods in the {@link org.apache.sling.jcr.classloader.internal.net.URLFactory} class.
+ * <p>
+ * This class is not intended to be subclassed or instantiated by clients.
+ *
+ * @author Felix Meschberger
+ *
+ * @see org.apache.sling.jcr.classloader.internal.net.JCRJarURLConnection
+ * @see org.apache.sling.jcr.classloader.internal.net.URLFactory
+ * @see org.apache.sling.jcr.classloader.internal.net.URLFactory#createJarURL(Session, String, String)
+ */
+class JCRJarURLHandler extends JCRURLHandler {
+
+    /**
+     * Creates an instance of this handler class.
+     *
+     * @param session The <code>Session</code> supporting this handler. This
+     *      must not be <code>null</code>.
+     *
+     * @throws NullPointerException if <code>session</code> is <code>null</code>.
+     */
+    JCRJarURLHandler(Session session) {
+        super(session);
+    }
+
+    //---------- URLStreamHandler abstracts ------------------------------------
+
+    /**
+     * Gets a connection object to connect to an JCRJar URL.
+     *
+     * @param url The JCRJar URL to connect to.
+     *
+     * @return An instance of the {@link JCRJarURLConnection} class.
+     *
+     * @see JCRJarURLConnection
+     */
+    protected URLConnection openConnection(URL url) {
+        return new JCRJarURLConnection(url, this);
+    }
+
+    /**
+     * Parses the string representation of a <code>URL</code> into a
+     * <code>URL</code> object.
+     * <p>
+     * If there is any inherited context, then it has already been copied into
+     * the <code>URL</code> argument.
+     * <p>
+     * The <code>parseURL</code> method of <code>URLStreamHandler</code>
+     * parses the string representation as if it were an <code>http</code>
+     * specification. Most URL protocol families have a similar parsing. A
+     * stream protocol handler for a protocol that has a different syntax must
+     * override this routine.
+     *
+     * @param url the <code>URL</code> to receive the result of parsing the
+     *            spec.
+     * @param spec the <code>String</code> representing the URL that must be
+     *            parsed.
+     * @param start the character index at which to begin parsing. This is just
+     *            past the '<code>:</code>' (if there is one) that specifies
+     *            the determination of the protocol name.
+     * @param limit the character position to stop parsing at. This is the end
+     *            of the string or the position of the "<code>#</code>"
+     *            character, if present. All information after the sharp sign
+     *            indicates an anchor.
+     */
+    protected void parseURL(URL url, String spec, int start, int limit) {
+        // protected void parseURL(URL url, String s, int i, int j)
+
+        String file = null;
+        String ref = null;
+
+        // split the reference and file part
+        int hash = spec.indexOf('#', limit);
+        boolean emptyFile = hash == start;
+        if (hash > -1) {
+            ref = spec.substring(hash + 1, spec.length());
+            if (emptyFile) {
+                file = url.getFile();
+            }
+        }
+
+        boolean isSpecAbsolute = spec.substring(0, 4).equalsIgnoreCase("jar:");
+        spec = spec.substring(start, limit);
+
+        if (isSpecAbsolute) {
+
+            // get the file part from the absolute spec
+            file = parseAbsoluteSpec(spec);
+
+        } else if (!emptyFile) {
+
+            // build the file part from the url and relative spec
+            file = parseContextSpec(url, spec);
+
+            // split archive and entry names
+            int bangSlash = indexOfBangSlash(file);
+            String archive = file.substring(0, bangSlash);
+            String entry = file.substring(bangSlash);
+
+            // collapse /../, /./ and //
+            entry = canonizeString(entry);
+
+            file = archive + entry;
+
+        }
+
+        setURL(url, "jar", "", -1, null, null, file, null, ref);
+    }
+
+    //---------- internal -----------------------------------------------------
+
+    /**
+     * Finds the position of the bang slash (!/) in the file part of the URL.
+     */
+    static int indexOfBangSlash(String file) {
+
+        for (int i = file.length(); (i = file.lastIndexOf('!', i)) != -1; i--) {
+            if (i != file.length() - 1 && file.charAt(i + 1) == '/') {
+                return i + 1;
+            }
+        }
+
+        return -1;
+    }
+
+    /**
+     * Parses the URL spec and checks whether it contains a bang slash and
+     * whether it would get a valid URL. Returns the same value if everything is
+     * fine else a <code>NullPointerException</code> is thrown.
+     *
+     * @param spec The URL specification to check.
+     * @return The <code>spec</code> if everything is ok.
+     * @throws NullPointerException if either no bang slash is contained in the
+     *             spec or if the spec without the bang slash part would not be
+     *             a valid URL.
+     */
+    private String parseAbsoluteSpec(String spec) {
+
+        // find and check bang slash
+        int bangSlash = indexOfBangSlash(spec);
+        if (bangSlash == -1) {
+            throw new NullPointerException("no !/ in spec");
+        }
+
+        try {
+
+            String testSpec = spec.substring(0, bangSlash - 1);
+            URI uri = new URI(testSpec);
+
+            // verify the scheme is the JCR Repository Scheme
+            if (!URLFactory.REPOSITORY_SCHEME.equals(uri.getScheme())) {
+                throw new URISyntaxException(testSpec,
+                    "Unsupported Scheme " + uri.getScheme(), 0);
+            }
+
+        } catch (URISyntaxException use) {
+
+            throw new NullPointerException("invalid url: " + spec + " (" + use
+                + ")");
+
+        }
+
+        return spec;
+    }
+
+    /**
+     * Merges the specification and the file part of the URL respecting the bang
+     * slashes. If the specification starts with a slash, it is regarded as a
+     * complete path of a archive entry and replaces an existing archive entry
+     * specification in the url. Examples :<br>
+     * <table>
+     * <tr>
+     * <th align="left">file
+     * <th align="left">spec
+     * <th align="left">result
+     * <tr>
+     * <td>/some/file/path.jar!/
+     * <td>/some/entry/path
+     * <td>/some/file/path.jar!/some/entry/path
+     * <tr>
+     * <td>/some/file/path.jar!/some/default
+     * <td>/some/entry/path
+     * <td>/some/file/path.jar!/some/entry/path </table>
+     * <p>
+     * If the specification is not absolutes it replaces the last file name part
+     * if the file name does not end with a slash. Examples :<br>
+     * <table>
+     * <tr>
+     * <th align="left">file
+     * <th align="left">spec
+     * <th align="left">result
+     * <tr>
+     * <td>/some/file/path.jar!/
+     * <td>/some/entry/path
+     * <td>/some/file/path.jar!/some/entry/path
+     * <tr>
+     * <td>/some/file/path.jar!/some/default
+     * <td>/some/entry/path
+     * <td>/some/file/path.jar!/some/entry/path </table>
+     *
+     * @param url The <code>URL</code> whose file part is used
+     * @param spec The specification to merge with the file part
+     * @throws NullPointerException If the specification starts with a slash and
+     *             the URL does not contain a slash bang or if the specification
+     *             does not start with a slash and the file part of the URL does
+     *             is not an absolute file path.
+     */
+    private String parseContextSpec(URL url, String spec) {
+
+        // spec is relative to this file
+        String file = url.getFile();
+
+        // if the spec is absolute path, it is an absolute entry spec
+        if (spec.startsWith("/")) {
+
+            // assert the bang slash in the original URL
+            int bangSlash = indexOfBangSlash(file);
+            if (bangSlash == -1) {
+                throw new NullPointerException("malformed context url:" + url
+                    + ": no !/");
+            }
+
+            // remove bang slash part from the original file
+            file = file.substring(0, bangSlash);
+        }
+
+        // if the file is not a directory and spec is a relative file path
+        if (!file.endsWith("/") && !spec.startsWith("/")) {
+
+            // find the start of the file name in the url file path
+            int lastSlash = file.lastIndexOf('/');
+            if (lastSlash == -1) {
+                throw new NullPointerException("malformed context url:" + url);
+            }
+
+            // cut off the file name from the URL file path
+            file = file.substring(0, lastSlash + 1);
+        }
+
+        // concat file part and the spec now
+        return file + spec;
+    }
+
+    public String canonizeString(String s) {
+        int i = 0;
+        int k = s.length();
+        while ((i = s.indexOf("/../")) >= 0)
+            if ((k = s.lastIndexOf('/', i - 1)) >= 0)
+                s = s.substring(0, k) + s.substring(i + 3);
+            else
+                s = s.substring(i + 3);
+        while ((i = s.indexOf("/./")) >= 0)
+            s = s.substring(0, i) + s.substring(i + 2);
+        while (s.endsWith("/..")) {
+            int j = s.indexOf("/..");
+            int l;
+            if ((l = s.lastIndexOf('/', j - 1)) >= 0)
+                s = s.substring(0, l + 1);
+            else
+                s = s.substring(0, j);
+        }
+        if (s.endsWith("/.")) s = s.substring(0, s.length() - 1);
+        return s;
+    }
+}
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRURLConnection.java b/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRURLConnection.java
new file mode 100644
index 0000000..9e1471a
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRURLConnection.java
@@ -0,0 +1,778 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal.net;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import javax.jcr.Item;
+import javax.jcr.Node;
+import javax.jcr.Property;
+import javax.jcr.PropertyType;
+import javax.jcr.RepositoryException;
+import javax.jcr.Session;
+
+import org.apache.sling.jcr.classloader.internal.Util;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+
+/**
+ * The <code>JCRURLConnection</code> is the <code>URLConnection</code>
+ * implementation to access the data addressed by a JCR Repository URL.
+ * <p>
+ * As the primary use of a <code>URLConnection</code> and thus the
+ * <code>JCRURLConnection</code> is to provide access to the content of a
+ * resource identified by the URL, it is the primary task of this class to
+ * identify and access a repository <code>Property</code> based on the URL. This
+ * main task is executed in the {@link #connect()} method.
+ * <p>
+ * Basically the guideposts to access content from a JCR Repository URL are
+ * the following:
+ * <ul>
+ * <li>The URL must ultimately resolve to a repository property to provide
+ *      content.
+ * <li>If the URL itself is the path to a property, that property is used to
+ *      provide the content.
+ * <li>If the URL is a path to a node, either the
+ *      <code>jcr:content/jcr:data</code> or <code>jcr:data</code> property is
+ *      used or the primary item chain starting with this node is followed until
+ *      no further primary items exist. If the final item is a property, that
+ *      property is used to provide the content.
+ * <li>If neither of the above methods resolve to a property, the
+ *      {@link #connect()} fails and access to the content is not possible.
+ * </ul>
+ * <p>
+ * After having connected the property is available through the
+ * {@link #getProperty()} method. Other methods exist to retrieve repository
+ * related information defined when creating the URL: {@link #getSession()} to
+ * retrieve the session of the URL, {@link #getPath()} to retrieve the path
+ * with which the URL was created and {@link #getItem()} to retrieve the item
+ * with which the URL was created. The results of calling {@link #getProperty()}
+ * and {@link #getItem()} will be the same if the URL directly addressed the
+ * property. If the URL addressed the node whose primary item chain ultimately
+ * resolved to the property, the {@link #getItem()} will return the node and
+ * {@link #getProperty()} will return the resolved property.
+ * <p>
+ * A note on the <code>InputStream</code> available from
+ * {@link #getInputStream()}: Unlike other implementations - for example
+ * for <code>file:</code> or <code>http:</code> URLs - which return the same
+ * stream on each call, this implementation returns a new stream on each
+ * invocation.
+ * <p>
+ * The following header fields are implemented by this class:
+ * <dl>
+ * <dt><code>Content-Length</code>
+ * <dd>The size of the content is filled from the <code>Property.getLength()</code>
+ *      method, which returns the size in bytes of the property's value for
+ *      binary values and the number of characters used for the string
+ *      representation of the value for all other value types.
+ *
+ * <dt><code>Content-Type</code>
+ * <dd>The content type is retrieved from the <code>jcr:mimeType</code>
+ *      property of the property's parent node if existing. Otherwise the
+ *      <code>guessContentTypeFromName</code> method is called on the
+ *      {@link #getPath() path}. If this does not yield a content type, it is
+ *      set to <code>application/octet-stream</code> for binary properties and
+ *      to <code>text/plain</code> for other types.
+ *
+ * <dt><code>Content-Enconding</code>
+ * <dd>The content encoding is retrieved from the <code>jcr:econding</code>
+ *      property of the property's parent node if existing. Otherwise this
+ *      header field remains undefined (aka <code>null</code>).
+ *
+ * <dt><code>Last-Modified</code>
+ * <dd>The last modified type is retrieved from the <code>jcr:lastModified</code>
+ *      property of the property's parent node if existing. Otherwise the last
+ *      modification time is set to zero.
+ * </dl>
+ * <p>
+ * This class is not intended to be subclassed or instantiated by clients.
+ */
+public class JCRURLConnection extends URLConnection {
+
+    /** Default logging */
+    private static final Logger log =
+        LoggerFactory.getLogger(JCRURLConnection.class);
+
+    /**
+     * The name of the header containing the content size (value is
+     * "content-length").
+     */
+    protected static final String CONTENT_LENGTH = "content-length";
+
+    /**
+     * The name of the header containing the MIME type of the content (value is
+     * "content-type").
+     */
+    protected static final String CONTENT_TYPE = "content-type";
+
+    /**
+     * The name of the header containing the content encoding (value is
+     * "content-encoding").
+     */
+    protected static final String CONTENT_ENCODING = "content-encoding";
+
+    /**
+     * The name of the header containing the last modification time stamp of
+     * the content (value is "last-modified").
+     */
+    protected static final String LAST_MODIFIED = "last-modified";
+
+    /**
+     * The default content type name for binary properties accessed by this
+     * connection (value is "application/octet-stream").
+     * @see #connect()
+     */
+    protected static final String APPLICATION_OCTET = "application/octet-stream";
+
+    /**
+     * The default content type name for non-binary properties accessed by this
+     * connection (value is "text/plain").
+     * @see #connect()
+     */
+    protected static final String TEXT_PLAIN = "text/plain";
+
+    /**
+     * The handler associated with the URL of this connection. This handler
+     * provides the connection with access to the repository and the item
+     * underlying the URL.
+     */
+    private final JCRURLHandler handler;
+
+    /**
+     * The {@link FileParts} encapsulating the repository name, workspace name,
+     * item path and optional archive entry path contained in the file part
+     * of the URL. This field is set on-demand by the {@link #getFileParts()}
+     * method.
+     *
+     * @see #getFileParts()
+     */
+    private FileParts fileParts;
+
+    /**
+     * The <code>Item</code> addressed by the path of this connection's URL.
+     * This field is set on-demand by the {@link #getItem()} method.
+     *
+     * @see #getItem()
+     */
+    private Item item;
+
+    /**
+     * The <code>Property</code> associated with the URLConnection. The field
+     * is only set after the connection has been successfully opened.
+     *
+     * @see #getProperty()
+     * @see #connect()
+     */
+    private Property property;
+
+    /**
+     * The (guessed) content type of the data. Currently the content type is
+     * guessed based on the path name of the page or the binary attribute of the
+     * atom.
+     * <p>
+     * Implementations are free to decide, how to define the content type. But
+     * they are required to set the type in the {@link #connect(Ticket)}method.
+     *
+     * @see #getContentType()
+     * @see #connect()
+     */
+    private String contentType;
+
+    /**
+     * The (guessed) content encoding of the data. Currently the content type is
+     * guessed based on the path name of the page or the binary attribute of the
+     * atom.
+     * <p>
+     * Implementations are free to decide, how to define the content type. But
+     * they are required to set the type in the {@link #connect(Ticket)}method.
+     *
+     * @see #getContentEncoding()
+     * @see #connect()
+     */
+    private String contentEncoding;
+
+    /**
+     * The content lentgh of the data, which is the size field of the atom
+     * status information of the base atom.
+     * <p>
+     * Implementations are free to decide, how to define the content length. But
+     * they are required to set the type in the {@link #connect(Ticket)}method.
+     *
+     * @see #getContentLength()
+     * @see #connect()
+     */
+    private int contentLength;
+
+    /**
+     * The last modification time in milliseconds since the epoch (1970/01/01)
+     * <p>
+     * Implementations are free to decide, how to define the last modification
+     * time. But they are required to set the type in the
+     * {@link #connect(Ticket)}method.
+     *
+     * @see #getLastModified()
+     * @see #connect()
+     */
+    private long lastModified;
+
+    /**
+     * Creates an instance of this class for the given <code>url</code>
+     * supported by the <code>handler</code>.
+     *
+     * @param url The URL to base the connection on.
+     * @param handler The URL handler supporting the given URL.
+     */
+    JCRURLConnection(URL url, JCRURLHandler handler) {
+        super(url);
+        this.handler = handler;
+    }
+
+    /**
+     * Returns the current session of URL.
+     * <p>
+     * Calling this method does not require this connection being connected.
+     */
+    public Session getSession() {
+        return handler.getSession();
+    }
+
+    /**
+     * Returns the path to the repository item underlying the URL of this
+     * connection.
+     * <p>
+     * Calling this method does not require this connection being connected.
+     */
+    public String getPath() {
+        return getFileParts().getPath();
+    }
+
+    /**
+     * Returns the repository item underlying the URL of this connection
+     * retrieved through the path set on the URL.
+     * <p>
+     * Calling this method does not require this connection being connected.
+     *
+     * @throws IOException If the item has to be retrieved from the repository
+     *      <code>Session</code> of this connection and an error occurrs. The
+     *      cause of the exception will refer to the exception thrown from the
+     *      repository. If the path addresses a non-existing item, the cause
+     *      will be a <code>PathNotFoundException</code>.
+     */
+    public Item getItem() throws IOException {
+        if (item == null) {
+            try {
+                item = getSession().getItem(getPath());
+            } catch (RepositoryException re) {
+                throw failure("getItem", re.toString(), re);
+            }
+        }
+
+        return item;
+    }
+
+    /**
+     * Returns the repository <code>Property</code> providing the contents of
+     * this connection.
+     * <p>
+     * Calling this method forces the connection to be opened by calling the
+     * {@link #connect()} method.
+     *
+     * @throws IOException May be thrown by the {@link #connect()} method called
+     *      by this method.
+     *
+     * @see #connect()
+     */
+    public Property getProperty() throws IOException {
+        // connect to set the property value
+        connect();
+
+        return property;
+    }
+
+    //---------- URLConnection overwrites -------------------------------------
+
+    /**
+     * Connects to the URL setting the header fields and preparing for the
+     * {@link #getProperty()} and {@link #getInputStream()} methods.
+     * <p>
+     * The following algorithm is applied:
+     * <ol>
+     * <li>The repository item is retrieved from the URL's
+     *      <code>URLHandler</code>.
+     * <li>If the item is a node, the <code>getPrimaryItem</code> method is
+     *      called on that node. If the node has no primary item, the connection
+     *      fails.
+     * <li>If the item - either from the handler or after calling
+     *      <code>getPrimaryItem</code> is still a node, this method fails
+     *      because a <code>Property</code> is required for a successfull
+     *      connection.
+     * <li>If the property found above is a multi-valued property, connection
+     *      fails, because multi-valued properties are not currently supported.
+     * <li>The content length header field is set from the property length
+     *      (<code>Property.getLength())</code>).
+     * <li>The header fields for the content type, content encoding and last
+     *      modification time are set from the <code>jcr:mimeType</code>,
+     *      <code>jcr:encoding</code>, and <code>jcr:lastModification</code>
+     *      properties of the property's parent node if existing. Otherwise the
+     *      content encoding field is set to <code>null</code> and the last
+     *      modification time is set to zero. The content type field is guessed
+     *      from the name of the URL item. If the content type cannot be
+     *      guessed, it is set to <code>application/octet-stream</code> if the
+     *      property is of binary type or <code>text/plain</code> otherwise.
+     * </ol>
+     * <p>
+     * When this method successfully returns, this connection is considered
+     * connected. In case of an exception thrown, the connection is not
+     * connected.
+     *
+     * @throws IOException if an error occurrs retrieving the data property or
+     *      any of the header field value properties or if any other errors
+     *      occurrs. Any cuasing exception is set as the cause of this
+     *      exception.
+     */
+    public synchronized void connect() throws IOException {
+        // todo: The ContentBus URL must also contain version information on
+        if (!connected) {
+
+            // Get hold of the data
+            try {
+                // resolve the URLs item to a property
+                Property property = Util.getProperty(getItem());
+                if (property == null) {
+                    throw failure("connect",
+                        "Multivalue property not supported", null);
+                }
+
+                // values to set later
+                String contentType;
+                String contentEncoding = null; // no defined content encoding
+                int contentLength = (int) property.getLength();
+                long lastModified;
+
+                Node parent = property.getParent();
+                if (parent.hasProperty("jcr:lastModified")) {
+                    lastModified = parent.getProperty("jcr:lastModified").getLong();
+                } else {
+                    lastModified = 0;
+                }
+                
+                if (parent.hasProperty("jcr:mimeType")) {
+                    contentType = parent.getProperty("jcr:mimeType").getString();
+                } else {
+                    contentType = guessContentTypeFromName(getItem().getName());
+                    if (contentType == null) {
+                        contentType = (property.getType() == PropertyType.BINARY)
+                                ? APPLICATION_OCTET
+                                : TEXT_PLAIN;
+                    }
+                }
+                
+                if (parent.hasProperty("jcr:encoding")) {
+                    contentEncoding = parent.getProperty("jcr:encoding").getString();
+                } else {
+                    contentEncoding = null;
+                }
+
+                log.debug(
+                    "connect: Using property '{}' with content type '{}' for {} bytes",
+                    new Object[] { property.getPath(), contentType,
+                        new Integer(contentLength) });
+
+                // set the fields
+                setProperty(property);
+                setContentType(contentType);
+                setContentEncoding(contentEncoding);
+                setContentLength(contentLength);
+                setLastModified(lastModified);
+
+                // mark connection open
+                connected = true;
+
+            } catch (RepositoryException re) {
+                throw failure("connect", re.toString(), re);
+            }
+        }
+    }
+
+    /**
+     * Returns an input stream that reads from this open connection.
+     * <p>
+     * <b>NOTES:</b>
+     * <ul>
+     * <li>Each call to this method returns a new <code>InputStream</code>.
+     * <li>Do not forget to close the return stream when not used anymore for
+     *      the system to be able to free resources.
+     * </ul>
+     * <p>
+     * Calling this method implicitly calls {@link #connect()} to ensure the
+     * connection is open.
+     *
+     * @throws IOException if an error occurrs opening the connection through
+     *      {@link #connect()} or creating the <code>InputStream</code> on the
+     *      repository <code>Property</code>.
+     *
+     * @see #connect()
+     */
+    public InputStream getInputStream() throws IOException {
+        try {
+            return getProperty().getStream();
+        } catch (RepositoryException re) {
+            throw failure("getInputStream", re.toString(), re);
+        }
+    }
+
+    /**
+     * Gets the named header field. This implementation only supports the
+     * Content-Type, Content-Encoding, Content-Length and Last-Modified header
+     * fields. All other names return <code>null</code>.
+     * <p>
+     * Calling this method implicitly calls {@link #connect()} to ensure the
+     * connection is open.
+     *
+     * @param s The name of the header field value to return.
+     *
+     * @return The corresponding value or <code>null</code> if not one of the
+     *      supported fields or the named field's value cannot be retrieved
+     *      from the data source.
+     *
+     * @see #connect()
+     */
+    public String getHeaderField(String s) {
+        try {
+            connect();
+            if (CONTENT_LENGTH.equalsIgnoreCase(s)) {
+                return String.valueOf(contentLength);
+            } else if (CONTENT_TYPE.equalsIgnoreCase(s)) {
+                return contentType;
+            } else if (LAST_MODIFIED.equalsIgnoreCase(s)) {
+                return String.valueOf(lastModified);
+            } else if (CONTENT_ENCODING.equalsIgnoreCase(s)) {
+                return contentEncoding;
+            }
+        } catch (IOException ioe) {
+            log.info("getHeaderField: Problem connecting: " + ioe.toString());
+            log.debug("dump", ioe);
+        }
+
+        return null;
+    }
+
+    /**
+     * Get the header field with the given index. As with
+     * {@link #getHeaderField(String)} only Content-Length, Content-Type,
+     * Content-Encoding, and Last-Modified are supported. All indexes other
+     * than 0, 1, 2 or 3 will return <code>null</code>.
+     * <p>
+     * Calling this method implicitly calls {@link #connect()} to ensure the
+     * connection is open.
+     *
+     * @param i The index of the header field value to return.
+     *
+     * @return The corresponding value or <code>null</code> if not one of the
+     *      supported fields or the known field's value cannot be retrieved
+     *      from the data source.
+     *
+     * @see #connect()
+     */
+    public String getHeaderField(int i) {
+        try {
+            connect();
+            if (i == 0) {
+                return String.valueOf(contentLength);
+            } else if (i == 1) {
+                return contentType;
+            } else if (i == 2) {
+                return String.valueOf(lastModified);
+            } else if (i == 3) {
+                return contentEncoding;
+            }
+        } catch (IOException ioe) {
+            log.info("getHeaderField: Problem connecting: " + ioe.toString());
+            log.debug("dump", ioe);
+        }
+
+        return null;
+    }
+
+    /**
+     * Get the name of the header field with the given index. As with
+     * {@link #getHeaderField(String)} only Content-Length, Content-Type,
+     * Content-Encoding and Last-Modified are supported. All indexes other than
+     * 0, 1, 2 or 3 will return <code>null</code>.
+     * <p>
+     * Calling this method implicitly calls {@link #connect()} to ensure the
+     * connection is open.
+     *
+     * @param i The index of the header field name to return.
+     * @return The corresponding name or <code>null</code> if not one of the
+     *         supported fields.
+     *
+     * @see #connect()
+     */
+    public String getHeaderFieldKey(int i) {
+        try {
+            connect();
+            if (i == 0) {
+                return CONTENT_LENGTH;
+            } else if (i == 1) {
+                return CONTENT_TYPE;
+            } else if (i == 2) {
+                return LAST_MODIFIED;
+            } else if (i == 3) {
+                return CONTENT_ENCODING;
+            }
+        } catch (IOException ioe) {
+            log
+                .info("getHeaderFieldKey: Problem connecting: "
+                    + ioe.toString());
+            log.debug("dump", ioe);
+        }
+        return null;
+    }
+
+    /**
+     * Returns an unmodifiable map of all header fields. Each entry is indexed
+     * with a string key naming the field. The entry's value is an unmodifiable
+     * list of the string values of the respective header field.
+     * <p>
+     * Calling this method implicitly calls {@link #connect()} to ensure the
+     * connection is open.
+     *
+     * @return An unmodifiable map of header fields and their values. The map
+     *      will be empty if an error occurrs connecting through
+     *      {@link #connect()}.
+     *
+     * @see #connect()
+     */
+    public Map getHeaderFields() {
+        Map fieldMap = new HashMap();
+
+        try {
+            connect();
+            fieldMap.put(CONTENT_LENGTH, toList(String.valueOf(contentLength)));
+            fieldMap.put(CONTENT_TYPE, toList(contentType));
+            fieldMap.put(LAST_MODIFIED, toList(String.valueOf(lastModified)));
+
+            // only include if not null))
+            if (contentEncoding != null) {
+                fieldMap.put(CONTENT_ENCODING, toList(contentEncoding));
+            }
+        } catch (IOException ioe) {
+            log.info("getHeaderFields: Problem connecting: " + ioe.toString());
+            log.debug("dump", ioe);
+        }
+
+        return Collections.unmodifiableMap(fieldMap);
+    }
+
+    /**
+     * Returns the content type of the data as a string. This is just a
+     * perfomance convenience overwrite of the base class implementation.
+     * <p>
+     * Calling this method implicitly calls {@link #connect()} to ensure the
+     * connection is open.
+     *
+     * @return The content length of the data or <code>null</code> if the
+     *      content type cannot be derived from the data source.
+     *
+     * @see #connect()
+     */
+    public String getContentType() {
+        try {
+            connect();
+            return contentType;
+        } catch (IOException ioe) {
+            log.info("getContentType: Problem connecting: " + ioe.toString());
+            log.debug("dump", ioe);
+        }
+
+        return null;
+    }
+
+    /**
+     * Returns the content encoding of the data as a string. This is just a
+     * perfomance convenience overwrite of the base class implementation.
+     * <p>
+     * Calling this method implicitly calls {@link #connect()} to ensure the
+     * connection is open.
+     *
+     * @return The content encoding of the data or <code>null</code> if the
+     *      content encoding cannot be derived from the data source.
+     *
+     * @see #connect()
+     */
+    public String getContentEncoding() {
+        try {
+            connect();
+            return contentEncoding;
+        } catch (IOException ioe) {
+            log.info("getContentEncoding: Problem connecting: " + ioe.toString());
+            log.debug("dump", ioe);
+        }
+
+        return null;
+    }
+
+    /**
+     * Returns the content length of the data as an number. This is just a
+     * perfomance convenience overwrite of the base class implementation.
+     * <p>
+     * Calling this method implicitly calls {@link #connect()} to ensure the
+     * connection is open.
+     *
+     * @return The content length of the data or -1 if the content length cannot
+     *         be derived from the data source.
+     *
+     * @see #connect()
+     */
+    public int getContentLength() {
+        try {
+            connect();
+            return contentLength;
+        } catch (IOException ioe) {
+            log.info("getContentLength: Problem connecting: " + ioe.toString());
+            log.debug("dump", ioe);
+        }
+        return -1;
+    }
+
+    /**
+     * Returns the value of the <code>last-modified</code> header field. The
+     * result is the number of milliseconds since January 1, 1970 GMT.
+     * <p>
+     * Calling this method implicitly calls {@link #connect()} to ensure the
+     * connection is open.
+     *
+     * @return the date the resource referenced by this
+     *         <code>URLConnection</code> was last modified, or -1 if not
+     *         known.
+     *
+     * @see #connect()
+     */
+    public long getLastModified() {
+        try {
+            connect();
+            return lastModified;
+        } catch (IOException ioe) {
+            log.info("getLastModified: Problem connecting: " + ioe.toString());
+            log.debug("dump", ioe);
+        }
+        return -1;
+    }
+
+    //---------- implementation helpers ----------------------------------------
+
+    /**
+     * Returns the URL handler of the URL of this connection.
+     */
+    protected JCRURLHandler getHandler() {
+        return handler;
+    }
+
+    /**
+     * Returns the {@link FileParts} object which contains the decomposed file
+     * part of this connection's URL.
+     */
+    FileParts getFileParts() {
+        if (fileParts == null) {
+            fileParts = new FileParts(getURL().getFile());
+        }
+
+        return fileParts;
+    }
+
+    /**
+     * @param contentEncoding The contentEncoding to set.
+     */
+    protected void setContentEncoding(String contentEncoding) {
+        this.contentEncoding = contentEncoding;
+    }
+
+    /**
+     * @param contentLength The contentLength to set.
+     */
+    protected void setContentLength(int contentLength) {
+        this.contentLength = contentLength;
+    }
+
+    /**
+     * @param contentType The contentType to set.
+     */
+    protected void setContentType(String contentType) {
+        this.contentType = contentType;
+    }
+
+    /**
+     * @param lastModified The lastModified to set.
+     */
+    protected void setLastModified(long lastModified) {
+        this.lastModified = lastModified;
+    }
+
+    /**
+     * @param property The property to set.
+     */
+    protected void setProperty(Property property) {
+        this.property = property;
+    }
+
+    //---------- internal -----------------------------------------------------
+
+    /**
+     * Logs the message and returns an IOException to be thrown by the caller.
+     * The log message contains the caller name, the external URL form and the
+     * message while the IOException is only based on the external URL form and
+     * the message given.
+     *
+     * @param method The method in which the error occurred. This is used for
+     *            logging.
+     * @param message The message to log and set in the exception
+     * @param cause The cause of failure. May be <code>null</code>.
+     *
+     * @return The IOException the caller may throw.
+     */
+    protected IOException failure(String method, String message, Throwable cause) {
+        log.info(method + ": URL: " + url.toExternalForm() + ", Reason: "
+            + message);
+
+        if (cause != null) {
+            log.debug("dump", cause);
+        }
+
+        IOException ioe = new IOException(url.toExternalForm() + ": " + message);
+        ioe.initCause(cause);
+        return ioe;
+    }
+
+    /**
+     * Returns an unmodifiable list containing just the given string value.
+     */
+    private List toList(String value) {
+        String[] values = { value };
+        List valueList = Arrays.asList(values);
+        return Collections.unmodifiableList(valueList);
+    }
+}
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRURLHandler.java b/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRURLHandler.java
new file mode 100644
index 0000000..1fa72c6
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/net/JCRURLHandler.java
@@ -0,0 +1,147 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal.net;
+
+import java.net.URL;
+import java.net.URLConnection;
+import java.net.URLStreamHandler;
+
+import javax.jcr.Session;
+
+/**
+ * The <code>JCRURLHandler</code> is the <code>URLStreamHandler</code> for
+ * JCR Repository URLs identified by the scheme <code>jcr</code>.
+ * <p>
+ * JCR Repository URLs have not been standardized yet and may only be created
+ * in the context of an existing <code>Session</code>. Therefore this handler
+ * is not globally available and JCR Repository URLs may only be created through
+ * the factory methods in the {@link org.apache.sling.jcr.classloader.internal.net.URLFactory}
+ * class.
+ * <p>
+ * This class is not intended to be subclassed or instantiated by clients.
+ *
+ * @author Felix Meschberger
+ *
+ * @see org.apache.sling.jcr.classloader.internal.net.JCRURLConnection
+ * @see org.apache.sling.jcr.classloader.internal.net.URLFactory
+ * @see org.apache.sling.jcr.classloader.internal.net.URLFactory#createURL(Session, String)
+ */
+class JCRURLHandler extends URLStreamHandler {
+
+    /**
+     * The session used to create this handler, which is also used to open
+     * the connection object.
+     *
+     * @see #getSession()
+     */
+    private final Session session;
+
+    /**
+     * Creates a new instance of the <code>JCRURLHandler</code> with the
+     * given session.
+     *
+     * @param session The <code>Session</code> supporting this handler. This
+     *      must not be <code>null</code>.
+     *
+     * @throws NullPointerException if <code>session</code> is <code>null</code>.
+     */
+    JCRURLHandler(Session session) {
+        if (session == null) {
+            throw new NullPointerException("session");
+        }
+
+        this.session = session;
+    }
+
+    /**
+     * Returns the session supporting this handler.
+     */
+    Session getSession() {
+        return session;
+    }
+
+    //---------- URLStreamHandler abstracts ------------------------------------
+
+    /**
+     * Gets a connection object to connect to an JCR Repository URL.
+     *
+     * @param url The JCR Repository URL to connect to.
+     *
+     * @return An instance of the {@link JCRURLConnection} class.
+     *
+     * @see JCRURLConnection
+     */
+    protected URLConnection openConnection(URL url) {
+        return new JCRURLConnection(url, this);
+    }
+
+    /**
+     * Checks the new <code>authority</code> and <code>path</code> before
+     * actually setting the values on the url calling the base class
+     * implementation.
+     * <p>
+     * We check the authority to not have been modified from the original URL,
+     * as the authority is dependent on the repository <code>Session</code> on
+     * which this handler is based and which was used to create the original
+     * URL. Likewise the repository and workspace name parts of the path must
+     * not have changed.
+     *
+     * @param u the URL to modify.
+     * @param protocol the protocol name.
+     * @param host the remote host value for the URL.
+     * @param port the port on the remote machine.
+     * @param authority the authority part for the URL.
+     * @param userInfo the userInfo part of the URL.
+     * @param path the path component of the URL.
+     * @param query the query part for the URL.
+     * @param ref the reference.
+     *
+     * @throws IllegalArgumentException if the authority or the repository name
+     *             or workspace name parts of the path has changed.
+     */
+    protected void setURL(URL u, String protocol, String host, int port,
+        String authority, String userInfo, String path, String query, String ref) {
+
+        // check for authority
+        if (u.getAuthority() != authority) {
+            if (u.getAuthority() == null) {
+                if (authority != null) {
+                    throw new IllegalArgumentException("Authority " +
+                        authority + " not supported by this handler");
+                }
+            } else if (!u.getAuthority().equals(authority)) {
+                throw new IllegalArgumentException("Authority " +
+                    authority + " not supported by this handler");
+            }
+        }
+
+        // check for repository and/or workspace modifications
+        FileParts newParts = new FileParts(path);
+        if (!"_".equals(newParts.getRepository())) {
+            throw new IllegalArgumentException("Repository " +
+                newParts.getRepository() + " not supported by this handler");
+        }
+        if (!session.getWorkspace().getName().equals(newParts.getWorkspace())) {
+            throw new IllegalArgumentException("Workspace " +
+                newParts.getWorkspace() + " not supported by this handler");
+        }
+
+        // finally set the new values on the URL
+        super.setURL(u, protocol, host, port, authority, userInfo, path, query,
+            ref);
+    }
+}
diff --git a/src/main/java/org/apache/sling/jcr/classloader/internal/net/URLFactory.java b/src/main/java/org/apache/sling/jcr/classloader/internal/net/URLFactory.java
new file mode 100644
index 0000000..834480a
--- /dev/null
+++ b/src/main/java/org/apache/sling/jcr/classloader/internal/net/URLFactory.java
@@ -0,0 +1,99 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sling.jcr.classloader.internal.net;
+
+import java.net.MalformedURLException;
+import java.net.URL;
+
+import javax.jcr.Session;
+
+/**
+ * The <code>URLFactory</code> class provides factory methods for creating
+ * JCR Repository and JCRJar URLs.
+ * <p>
+ * This class is not intended to be subclassed or instantiated by clients.
+ *
+ * @author Felix Meschberger
+ */
+public final class URLFactory {
+
+    /**
+     * The scheme for JCR Repository URLs (value is "jcr").
+     */
+    public static final String REPOSITORY_SCHEME = "jcr";
+
+    /**
+     * The scheme for JCRJar URLs (value is "jar").
+     */
+    public static final String REPOSITORY_JAR_SCHEME = "jar";
+
+    /** Private default constructor, not to be instantiated */
+    private URLFactory() {
+    }
+
+    /**
+     * Creates a new JCR Repository URL for the given session and item path.
+     *
+     * @param session The repository session providing access to the item.
+     * @param path The absolute path to the item. This must be an absolute
+     *      path with a leading slash character. If this is <code>null</code>
+     *      the root node path - <code>/</code> - is assumed.
+     *
+     * @return The JCR Repository URL
+     *
+     * @throws MalformedURLException If an error occurrs creating the
+     *      <code>URL</code> instance.
+     */
+    public static URL createURL(Session session, String path)
+        throws MalformedURLException {
+
+        return new URL(REPOSITORY_SCHEME, "", -1,
+            new FileParts(session, path, null).toString(),
+            new JCRURLHandler(session));
+    }
+
+    /**
+     * Creates a new JCRJar URL for the given session, archive and entry.
+     *
+     * @param session The repository session providing access to the archive.
+     * @param path The absolute path to the archive. This must either be the
+     *      property containing the archive or an item which resolves to such
+     *      a property through its primary item chain. This must be an absolute
+     *      path with a leading slash character. If this is <code>null</code>
+     *      the root node path - <code>/</code> - is assumed.
+     * @param entry The entry within the archive. If <code>null</code>, the URL
+     *      provides access to the archive itself.
+     *
+     * @return The JCRJar URL
+     *
+     * @throws MalformedURLException If an error occurrs creating the
+     *      <code>URL</code> instance.
+     */
+    public static URL createJarURL(Session session, String path, String entry)
+        throws MalformedURLException {
+
+        JCRJarURLHandler handler = new JCRJarURLHandler(session);
+        String file = createURL(session, path).toExternalForm();
+
+        // append entry spec if not null
+        if (entry != null) {
+            file += "!/" + entry;
+        }
+
+        return new URL(REPOSITORY_JAR_SCHEME, "", -1, file, handler);
+    }
+}

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