8315317: Add test for JDK-8262518

Reviewed-by: angorya

tests/system/src/test/java/test/javafx/embed/swing/SwingNodeContentMemoryLeakTest.java

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package test.javafx.embed.swing;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeTrue;
+
+import java.lang.ref.WeakReference;
+import java.lang.reflect.InvocationTargetException;
+import java.util.Collection;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.CountDownLatch;
+
+import javax.swing.JPanel;
+import javax.swing.SwingUtilities;
+
+import javafx.application.Application;
+import javafx.embed.swing.SwingNode;
+import javafx.scene.Scene;
+import javafx.scene.layout.Pane;
+import javafx.stage.Stage;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import com.sun.javafx.PlatformUtil;
+
+import test.util.Util;
+
+public class SwingNodeContentMemoryLeakTest {
+
+    static CountDownLatch launchLatch = new CountDownLatch(1);
+
+    //Keep week references to all panels that we've ever generated to see if any
+    //of them get collected.
+    private Collection<WeakReference<JPanel>> panels = new CopyOnWriteArrayList<>();
+    private int count = 0;
+    private int fail = 0;
+    private SwingNode node;
+    private long panelCount;
+
+    @BeforeClass
+    public static void setupOnce() {
+        Util.launch(launchLatch, 50, MyApp.class);
+    }
+
+    @AfterClass
+    public static void teardownOnce() {
+        Util.shutdown();
+    }
+
+    @Test
+    public void testSwingNodeContentMemoryLeak() throws InterruptedException,
+                                                        InvocationTargetException {
+        Util.runAndWait(() -> {
+            node = new SwingNode();
+            Pane root = new Pane();
+            root.getChildren().add(node);
+
+            Stage stage = new Stage();
+            Scene scene = new Scene(root, 150, 100);
+            stage.setScene(scene);
+        });
+
+        //Kick off a thread that repeatedly creates new JPanels and resets the swing node's content
+        new Thread(() -> {
+            while(count < 50) {
+                //Lets throw in a little sleep so we can read the output
+                try {
+                    Thread.sleep(100);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+
+                SwingUtilities.invokeLater(() -> {
+                    JPanel panel = new JPanel();
+                    panels.add(new WeakReference<>(panel));
+                    node.setContent(panel);
+                });
+
+                panelCount = panels.stream().filter(ref ->
+                                                     ref.get() != null).count();
+                System.out.println("iteration " + count + " Panels in memory: " + panelCount);
+
+                //I know this doesn't guarantee anything, but prompting a GC gives me more confidence that this
+                //truly is a bug.
+                System.gc();
+                count++;
+            }
+            // Check if panelCount has not increased beyond certain threshold
+            assertFalse(panelCount > count/2);
+
+        }).start();
+
+        // Invoke a noop on EDT thread and wait for a bit to make sure EDT processed node objects
+        SwingUtilities.invokeAndWait(() -> {});
+        Util.sleep(5000);
+    }
+
+    public static class MyApp extends Application {
+        @Override
+        public void start(Stage stage) throws Exception {
+            launchLatch.countDown();
+        }
+    }
+}