RFR: 8293444: Creating ScrollPane with same content component causes memory leak [v2]

[Ambarish Rapte]

On Fri, 16 Sep 2022 18:04:07 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> Using Weak*Listeners eliminates the memory leak.
>
> Andy Goryachev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8293444: memory buddy

modules/javafx.controls/src/test/java/test/javafx/scene/control/skin/ScrollPaneSkinTest.java line 36:

> 34: import org.junit.Before;
> 35: import org.junit.Ignore;
> 36: import org.junit.Test;

These got moved from line 51(without this PR), can restore this change.

modules/javafx.controls/src/test/java/test/javafx/scene/control/skin/ScrollPaneSkinTest.java line 875:

> 873: 
> 874:     /**
> 875:      * checks that there are no memory leaks when replacing scroll pane content

Minor rephrasing:

     * Test that ScrollPane object is not leaked when 'same' node
     * is used as content for different ScrollPane objects.

modules/javafx.controls/src/test/java/test/javafx/scene/control/skin/ScrollPaneSkinTest.java line 878:

> 876:      */
> 877:     @Test
> 878:     public void checkMemoryLeaks_JDK_8293444() {

may be rename to something similar as : `testScrollPaneObjLeakWhenUsedSameContent`

modules/javafx.controls/src/test/java/test/javafx/scene/control/skin/ScrollPaneSkinTest.java line 887:

> 885:         stage.setScene(new Scene(bp));
> 886:         stage.setWidth(600);
> 887:         stage.setHeight(600);

Minor: These are not required for the test. so can remove.

modules/javafx.controls/src/test/java/test/javafx/scene/control/skin/ScrollPaneSkinTest.java line 912:

> 910: 
> 911:         // one instance is still held by the 'content' label
> 912:         assertTrue("uncollected objects=" + ct, ct <= 1);

May be the assert can be updated to:


        assertEquals("One instance should be held by the 'content' label", 1, ct);

        content = null;
        ct = 0;
        for (WeakReference<ScrollPane> ref : refs) {
            JMemoryBuddy.checkCollectable(ref);
            if (ref.get() != null) {
                ct++;
            }
        }
        assertEquals(ct + " References of ScrollPane are not freed.", 0, ct);

-------------

PR: https://git.openjdk.org/jfx/pull/900