[jira] [Commented] (WINK-363) Failure to find array entity providers (such as ByteArrayProvider) in Java 7

["Michael Fiedler (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/WINK-363?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13425978#comment-13425978 ] 

Michael Fiedler commented on WINK-363:
--------------------------------------

[~kevan] Any chance of getting this in a build?  I verified the proposed patch on 1.2.0 and can confirm it fixes the issue.   The wink-commons JUnits actually fail without the patch on and pass with it on.  I can open a separate issue for the JUNit failure if that helps.

My JRE:

java version "1.7.0"
Java(TM) SE Runtime Environment (build pwa6470sr1-20120405_01(SR1))
IBM J9 VM (build 2.6, JRE 1.7.0 Windows Server 2008 R2 amd64-64 20120322_106209
(JIT enabled, AOT enabled)
J9VM - R26_Java726_SR1_20120322_1720_B106209
JIT  - r11_20120322_22976
GC   - R26_Java726_SR1_20120322_1720_B106209
J9CL - 20120322_106209)
JCL - 20120322_01 based on Oracle 7u3-b05
                
> Failure to find array entity providers (such as ByteArrayProvider) in Java 7
> ----------------------------------------------------------------------------
>
>                 Key: WINK-363
>                 URL: https://issues.apache.org/jira/browse/WINK-363
>             Project: Wink
>          Issue Type: Bug
>          Components: Providers
>    Affects Versions: 1.1.3
>         Environment: Linux, Java 1.7.0-b147
>            Reporter: Georg Sander
>         Attachments: GenericsUtils.java
>
>
> The ByteArrayProvider is properly registered and is found through ProvidersRegistry in Java 6,but not in Java 7. The effect is a consequence of Java bug http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5041784 which got fixed in Java 7. It can also affect other array entity providers.
> Explanation: 
> ProvidersRegistry collects the providers for the target type byte[] by checking whether the provider type and the target type are assignable. The corresponding utilities are in GenericsUtils. To determine the provider type, GenericsUtil.getGenericInterfaceParamType retrieves the type from the generic interfaces of ByteArrayProvider. The type parameters in the generic interfaces are represented as java.lang.reflect.Type in Java 6 but as java.lang.Class in Java 7. As consequence, the method GenericsUtils.isAssignableFrom fails to see that the type parameter is an array, hence it returns that byte[] is not assignable to the retrieved type of ByteArrayProvider.
> Here is a simple Java program that explains the difference between Java 6 and Java 7. 
> In Java 6, the output is:
> Type Parameter byte[]
> Type Parameter class class sun.reflect.generics.reflectiveObjects.GenericArrayTypeImpl
> Is Generic Array true
> In Java 7, the output is:
> Type Parameter class [B
> Type Parameter class class java.lang.Class
> Is Generic Array false
> {code}
> import java.lang.reflect.GenericArrayType;
> import java.lang.reflect.ParameterizedType;
> import java.lang.reflect.Type;
> public class Test
> {
>   public static void main(String[] args) {
>     Class cls = ByteArrayProvider.class;
>     Type[] interfaces = cls.getGenericInterfaces();
>     for (Type type : interfaces) {
>       if (type instanceof ParameterizedType) {
>         ParameterizedType pType = (ParameterizedType)type;
>         Type t = pType.getActualTypeArguments()[0];
>         System.err.println("Type Parameter " + t);
>         System.err.println("Type Parameter class " + t.getClass());
>         System.err.println("Is Generic Array " + (t instanceof GenericArrayType));
>       }
>     }
>   }
> }
> interface MessageBodyWriter<T> { }
> class ByteArrayProvider implements MessageBodyWriter<byte[]> { }
> {code}
> I suggest the following fix in GenericsUtils (tested locally in Wink 1.1.3):
> {code:title=GenericsUtils.isAssignableFrom|borderStyle=solid}
>     public static boolean isAssignableFrom(Type type, Class<?> cls) {
>         if (cls.isArray()) {
>             if (type instanceof GenericArrayType) {
>                 GenericArrayType genericArray = (GenericArrayType)type;
>                 Class<?> componentType = cls.getComponentType();
>                 return isAssignableFrom(genericArray.getGenericComponentType(), componentType);
>             }
>             else if ((type instanceof Class<?>) && ((Class<?>)type).isArray()) {
>                 Class<?> componentType1 = ((Class<?>)type).getComponentType();
>                 Class<?> componentType2 = cls.getComponentType();
>                 return isAssignableFrom(componentType1, componentType2);
>             }
>         } else {
>             if (type instanceof GenericArrayType == false) {
>                 Class<?> classType = getClassType(type, null);
>                 if (classType == Object.class || classType.isAssignableFrom(cls)) {
>                     return true;
>                 }
>             }
>         }
>         return false;
>     }
> {code}

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