SYNOPSIS
--------
Generic cast error caused by fix for CR 4916620

OPERATING SYSTEM
----------------
All

FULL JDK VERSION
----------------
1.5.0_07 - Warning, no error.
1.5.0_08 - _28 - Error, instead of warning.
JDK 6 - Warning, no error.
JDK 7 - Warning, no error.

PROBLEM DESCRIPTION from LICENSEE
---------------------------------
The fix for CR 4916620 leads to a regression in javac. Code that previously compiled with a warning now fails to compile. The problem is limited to 5.0 - the Java 6 javac implementation compiles the code with just a warning, even though 4916620 was also fixed in 6 (perhaps there is some other fix that needs to be ported to 5.0?). JDK 7 throws
a warning, in

REPRODUCTION INSTRUCTIONS
-------------------------
Attempt to compile the attached testcase with the following command:

   javac -Xlint:unchecked WeakValueHashMap.java

You will see the following results:

1.5.0_07 and earlier:
=====================
WeakValueHashMap.java:9: warning: [unchecked] unchecked cast
found : java.lang.ref.Reference<capture of ? extends V>
required: WeakValueHashMap<K,V>.KeyWeakReference<V>
        KeyWeakReference<V> sr = (KeyWeakReference<V>) this.queue.poll();
                                                                      ^
1 warning
========

1.5.0_08 and later:
===================
WeakValueHashMap.java:9: inconvertible types
found : java.lang.ref.Reference<capture of ? extends V>
required: WeakValueHashMap<K,V>.KeyWeakReference<V>
        KeyWeakReference<V> sr = (KeyWeakReference<V>) this.queue.poll();
                                                                      ^
1 error
========

Any Java 6:
===========
WeakValueHashMap.java:9: warning: [unchecked] unchecked cast
found : java.lang.ref.Reference<capture#159 of ? extends V>
required: WeakValueHashMap<K,V>.KeyWeakReference<V>
        KeyWeakReference<V> sr = (KeyWeakReference<V>) this.queue.poll();
                                                                      ^
1 warning
========

JDK 7:
======
WeakValueHashMap.java:193: warning: [unchecked] unchecked cast
                KeyWeakReference<V> sr = (KeyWeakReference<V>) this.queue.poll();
                                                                              ^
  required: WeakValueHashMap<K,V>.KeyWeakReference<V>
  found: Reference<CAP#1>
  where V,K are type-variables:
    V extends Object declared in class WeakValueHashMap
    K extends Object declared in class WeakValueHashMap
  where CAP#1 is a fresh type-variable:
    CAP#1 extends V from capture of ? extends V
1 warning
=========


TESTCASE
--------

Testcase is attached to this bug report.

Note: To see the warnings with this code you need to comment out the
annotation below, which suppresses the warnings:
// @SuppressWarnings("unchecked")



WORKAROUND
----------
Change this line in the release() method from:

    KeyWeakReference<V> sr = (KeyWeakReference<V>) this.queue.poll();

to this:

    KeyWeakReference sr = (KeyWeakReference) this.queue.poll();

But it's not clear what side effects this may have.