Name: rmT116609 Date: 02/04/2003


FULL PRODUCT VERSION :
java version "1.4.1"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1-b21)
Java HotSpot(TM) Client VM (build 1.4.1-b21, mixed mode)

FULL OPERATING SYSTEM VERSION :
Microsoft Windows 2000 [Version 5.00.2195]

A DESCRIPTION OF THE PROBLEM :
If an Invocation Handler in a java.lang.reflect.Proxy
returns null and the Interface returns a basic datatype you
will receive a:
   java.lang.NullPointerException
   at $Proxy53.getLong(Unknown Source)
   ...

This exception does not explain the problem at all and
could lead to a difficult search for a solution.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Create an interface where a method returns a basic
datatype
2. Implement an Invocation handler that return null for
this method
3. Invoke the method through the interface with the proxy
as implementation

EXPECTED VERSUS ACTUAL BEHAVIOR :
Currently you get this exception:

   java.lang.NullPointerException
   at $Proxy53.getLong(Unknown Source)
   ...

I would like that either the Proxy returns the default
value of the given basic data type like 0 for a Number etc.
or throws a more appropriate exception.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
$ java ProxyTest
Exception in thread "main" java.lang.NullPointerException
        at $Proxy0.getLong(Unknown Source)
        at ProxyTest.main(ProxyTest.java:19)

---------- BEGIN SOURCE ----------
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class ProxyTest {
    public static void main( String[] pArguments ) {
        InvocationHandler lHandler = new InvocationHandler() {
            public Object invoke( Object proxy, Method method, Object[] args ) {
                return null;
            }
        };
        Class[] lInterfaces = new Class[ 1 ];
        lInterfaces[ 0 ] = Test.class;
        Test lTest = (Test) Proxy.newProxyInstance(
            Thread.currentThread().getContextClassLoader(),
            lInterfaces,
            lHandler
        );
        lTest.getLong( 1L );
    }
    
    public interface Test {
        public long getLong( long value );
    }
}
---------- END SOURCE ----------

CUSTOMER WORKAROUND :
Invocation Handler has to make sure that for a basic datatype never a "null" is returned.
(Review ID: 179179)
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