cannot instantiate class exception in Realm

[DU...@britbio.co.uk]

I posted this to tomcat-user but got no replies.
Perhaps tomcat-dev is more appropriate, as it is a programming problem. Can
anyone help?

Although I've been using tomacat for sometime, I'm now needeing to start on
some work to match up the authentication and authorisation within catalina
to our enviroment. To do this I'm putting together a LDAPRealm. I have a
rudimentary LDAPRealm that works fine on its own (outside catalina), but
when I run it within catalina I'm getting a cannot instantiate class
exception from within my code. Could someone give me a guide into what I'm
doing worong. It's probably pretty basic, but I'm new to this.

What I did:

created a org.apache.catalina.realm.MyRealm class that contains an
authenticate() method that connects to the LDAP server as follows

public Principal  authenticate(String username, String credentials) {
   
    MyRealmPrincipal principal = new MyRealmPrincipal(username);
    Hashtable env = new Hashtable(11);
    env.put(Context.PROVIDER_URL, 
	    "ldap://localhost:389/dc=britbio,dc=co,dc=uk");
    env.put(Context.SECURITY_PRINCIPAL, principal.getDistinguishedName());
    env.put(Context.SECURITY_CREDENTIALS, credentials);
    
    try {
      // Create the initial directory context
      DirContext ctx = new InitialDirContext(env);
      // if we get here then we've bound OK

      System.out.println("Authenticated for " +
principal.getDistinguishedName());

      // get the groups from the JNDI context and define them as roles
      getRoles(ctx, principal);

      // unbind
      ctx.close();

      return(principal);


    } catch (NamingException e) {
      // could not bind - wrong password?
      System.err.println("Failed to bind to directory for " + username);
      e.printStackTrace();
      return(null);
    } 


this code works fine on its own (outside catalina). However when I try to
run it within catalina (jar'd up the clases, put them in
$CATLINA_ROOT/server), my code gets called, but the bind to the LDAP server
fails with the following exception 


Failed to bind to directory for tom
javax.naming.NoInitialContextException: Cannot instantiate class:
com.sun.jndi.ldap.LdapCtxFactory.  Root exception is
java.lang.ClassCastException: com.sun.jndi.ldap.LdapCtxFactory
	at
javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:659)
	at
javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:250)
	at javax.naming.InitialContext.init(InitialContext.java:226)
	at javax.naming.InitialContext.<init>(InitialContext.java:202)
	at
javax.naming.directory.InitialDirContext.<init>(InitialDirContext.java:87)
	at
org.apache.catalina.realm.TimsRealm.authenticate(TimsRealm.java:109)
	at
org.apache.catalina.authenticator.BasicAuthenticator.findPrincipal(BasicAuth
enticator.java:214)
	at
org.apache.catalina.authenticator.BasicAuthenticator.authenticate(BasicAuthe
nticator.java:160)
	at
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase
.java:481)
	at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:975)
	at
org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2041)
	at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161
)
	at
org.apache.catalina.valves.ValveBase.invokeNext(ValveBase.java:242)
	at
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:414)
	at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:975)
	at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java
:159)
	at
org.apache.catalina.valves.ValveBase.invokeNext(ValveBase.java:242)
	at
org.apache.catalina.valves.RequestDumperValve.invoke(RequestDumperValve.java
:215)
	at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:975)
	at
org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:
818)
	at
org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:897)
	at java.lang.Thread.run(Thread.java:484)


Any ideas as to why this runs outside catalina and not inside it. The JVM,
and everything else I can think of is the same. My setup:
  Tomcat-4.0-b1
  JDK1.3
  Linux

many thanks

Tim


---------------------------------------------
Tim Dudgeon
dudgeon@britbio.co.uk



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