Name: rmT116609 Date: 06/10/2004


FULL PRODUCT VERSION :
java version "1.5.0-beta2"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta2-b51)
Java HotSpot(TM) Client VM (build 1.5.0-beta2-b51, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
The java.lang.reflect.ParameterizedType.equals() method of the object returned in the array from the java.lang.reflect.Method.getGenericParameterTypes() method does not seem to work in the way that the javadoc states.

When the types of the same method are accessed via two different Method objects testing those types with .equals() does not give the expected result. I expect them to be equal, they come from the same underlying method.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the program given below on Java 1.5 beta 2 on windows XP.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
type1 is a ParameterizedType
type2 is a ParameterizedType
type1(java.util.Set<java.lang.String>) equals type2(java.util.Set<java.lang.String>)


ACTUAL -
type1 is a ParameterizedType
type2 is a ParameterizedType
type1(java.util.Set<java.lang.String>) does not equal type2(java.util.Set<java.lang.String>)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
/*
 * ParameterizedTypeBug4.java
 *
 * Created on 08 June 2004, 16:57
 */

import java.util.*;
import java.lang.reflect.*;

/**
 * Testing the parameterized types for equality where the types have come from the same
 * method, accessed via two separate Method objects (method1 and method2) seems to give
 * the wrong result.
 * <p> The javadoc for ParameterizedType states "<i>Instances of classes that implement
 * this interface must implement an equals() method that equates any two instances that
 * share the same generic type declaration and have equal type parameters. </i>"
 * <p> On my system (Windows XP box) I get the following output:
 * <p><code>$ java -showversion -classpath . ParameterizedTypeBug4<br>
 * java version "1.5.0-beta2"<br>
 * Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta2-b51)<br>
 * Java HotSpot(TM) Client VM (build 1.5.0-beta2-b51, mixed mode, sharing)<br>
 * <br>
 * type1 is a ParameterizedType<br>
 * type2 is a ParameterizedType<br>
 * Type(java.util.Set&lt;java.lang.String&gt;) does not equal
 * Type(java.util.Set&lt;java.lang.String&gt;)</code>
 *
 * @author Charles Ren� Crichton
 */
public class ParameterizedTypeBug4 {
         
    public void aMethod(Set<String> names) {}

    public static void main(String[] args) throws Throwable {
         
        Method method1 = ParameterizedTypeBug4.class.getDeclaredMethod("aMethod", Set.class);
        Method method2 = ParameterizedTypeBug4.class.getDeclaredMethod("aMethod", Set.class);
   
        //Create a list of types for function1 and function2
        List<Type> types1 = Arrays.asList(method1.getGenericParameterTypes());
        List<Type> types2 = Arrays.asList(method2.getGenericParameterTypes());
        
Type type1 = types1.get(0);
Type type2 = types2.get(0);
            
if (type1 instanceof ParameterizedType) { System.out.println("type1 is a ParameterizedType"); }
if (type2 instanceof ParameterizedType) { System.out.println("type2 is a ParameterizedType"); }

        if (type1.equals(type2)) {
            System.out.println("type1("+type1+") equals type2("+type2+")");
        } else {
System.out.println("type1("+type1+") does not equal type2("+type2+")");
        }
    }

}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :

I was just going to use .toString() equality and hope that it works!
(Incident Review ID: 276747)
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