RFR: ForkJoinTask leaks exceptions

[Chris Hegarty]

This is a request to pull a small change to ForkJoinTask into jdk8, from 
the jsr166 CVS. This was first discussed over on c-i [1] a few weeks back.

diff -r 077237e4613f 
src/share/classes/java/util/concurrent/ForkJoinTask.java
--- a/src/share/classes/java/util/concurrent/ForkJoinTask.java  Mon Oct 
14 11:47:54 2013 +0100
+++ b/src/share/classes/java/util/concurrent/ForkJoinTask.java  Mon Oct 
14 16:44:01 2013 +0100
@@ -439,11 +439,13 @@ public abstract class ForkJoinTask<V> im
          final Throwable ex;
          ExceptionNode next;
          final long thrower;  // use id not ref to avoid weak cycles
+        final int hashCode;  // store task hashCode before weak ref 
disappears
          ExceptionNode(ForkJoinTask<?> task, Throwable ex, 
ExceptionNode next) {
              super(task, exceptionTableRefQueue);
              this.ex = ex;
              this.next = next;
              this.thrower = Thread.currentThread().getId();
+            this.hashCode = System.identityHashCode(task);
          }
      }

@@ -605,9 +607,9 @@ public abstract class ForkJoinTask<V> im
      private static void expungeStaleExceptions() {
          for (Object x; (x = exceptionTableRefQueue.poll()) != null;) {
              if (x instanceof ExceptionNode) {
-                ForkJoinTask<?> key = ((ExceptionNode)x).get();
+                int hashCode = ((ExceptionNode)x).hashCode;
                  ExceptionNode[] t = exceptionTable;
-                int i = System.identityHashCode(key) & (t.length - 1);
+                int i = hashCode & (t.length - 1);
                  ExceptionNode e = t[i];
                  ExceptionNode pred = null;
                  while (e != null) {


-Chris

[1] 
http://jsr166-concurrency.10961.n7.nabble.com/ForkJoinTask-leaks-exceptions-td10134.html