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  1. JDK
  2. JDK-8245282

Button/Combo Behavior: memory leak on dispose

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      Description

      The issue turned up in working on JDK-8244531. Failing test case:

          @Test
          public void testButtonBehaviorMemoryLeak() {
              Button control = new Button();
              WeakReference<BehaviorBase<?>> weakRef = new WeakReference<>(createBehavior(control));
              assertNotNull(weakRef.get());
              weakRef.get().dispose();
              attemptGC(weakRef);
              assertNull("behavior must be gc'ed", weakRef.get());
          }
          
      Problem missing removal of listener to control's focusedProperty. Actually, the behavior tries to but gets it wrong:

           // in constructor
           getNode().focusedProperty().addListener(this::focusChanged);

          // in dispose
          getNode().focusedProperty().removeListener(this::focusChanged);

      the incorrect assumption here is that the lambda being remove is the _same_ instance as the one added (which isn't the case)

      Fix is to have a field for the focusListener and add/remove that

          InvalidationListener listener = this::focusChanged;
          ...
           // in constructor
           getNode().focusedProperty().addListener(focusListener);

          // in dispose
          getNode().focusedProperty().removeListener(focusListener);

      Same issue with same reason and fix in ComboBoxBaseBehavior - will defer fix until JDK-8244531 is integrated (can then add cross-behavior test)

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              • Assignee:
                fastegal Jeanette Winzenburg
                Reporter:
                fastegal Jeanette Winzenburg
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                • Created:
                  Updated:
                  Resolved: