8300944: Test vmTestbase/gc/gctests/WeakReference/weak005/weak005.java fails with "Last weak reference has not been cleared"

[shivshah-oracle]

The test builds a chain of weak references, clears the array entries from the beginning, and expects the final reference to be cleared by a full GC. If GC runs just before the penultimate entry is cleared, that reference is still strongly reachable from the array while its referent is not. GC may clear it and place it on the pending reference list, which keeps the reference object alive until the reference handler processes it. Clearing its array entry afterward does not remove that reachability, so the final reference may legally remain uncleared.

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Issue

• JDK-8300944: Test vmTestbase/gc/gctests/WeakReference/weak005/weak005.java fails with "Last weak reference has not been cleared" (Bug - P4)

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