6505523: NullPointerException in BasicTreeUI when a node is removed by expansion listener

Reviewed-by: rupashka

src/share/classes/javax/swing/plaf/basic/BasicTreeUI.java

@@ -1932,20 +1932,22 @@ public class BasicTreeUI extends TreeUI
             else {
                 Rectangle   beginRect = getPathBounds(tree, getPathForRow
                                                       (tree, beginRow));
-                Rectangle   visRect = tree.getVisibleRect();
-                Rectangle   testRect = beginRect;
-                int         beginY = beginRect.y;
-                int         maxY = beginY + visRect.height;
-
-                for(int counter = beginRow + 1; counter <= endRow; counter++) {
-                    testRect = getPathBounds(tree,
-                                             getPathForRow(tree, counter));
-                    if((testRect.y + testRect.height) > maxY)
-                        counter = endRow;
+                if (beginRect != null) {
+                    Rectangle   visRect = tree.getVisibleRect();
+                    Rectangle   testRect = beginRect;
+                    int         beginY = beginRect.y;
+                    int         maxY = beginY + visRect.height;
+
+                    for(int counter = beginRow + 1; counter <= endRow; counter++) {
+                            testRect = getPathBounds(tree,
+                                    getPathForRow(tree, counter));
+                        if((testRect.y + testRect.height) > maxY)
+                                counter = endRow;
+                            }
+                        tree.scrollRectToVisible(new Rectangle(visRect.x, beginY, 1,
+                                                      testRect.y + testRect.height-
+                                                      beginY));
                 }
-                tree.scrollRectToVisible(new Rectangle(visRect.x, beginY, 1,
-                                                  testRect.y + testRect.height-
-                                                  beginY));
             }
         }
     }
@@ -3485,7 +3487,7 @@ public class BasicTreeUI extends TreeUI
             }
 
             Rectangle bounds = getPathBounds(tree, path);
-            if (y > (bounds.y + bounds.height)) {
+            if (bounds == null || y > (bounds.y + bounds.height)) {
                 return false;
             }
 

test/javax/swing/JTree/6505523/bug6505523.java

+/*
+ * Copyright (c) 2012, 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.
+ *
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 6505523
+ * @summary NullPointerException in BasicTreeUI when a node is removed by expansion listener
+ * @author Alexandr Scherbatiy
+ * @run main bug6505523
+ */
+import java.awt.Point;
+import java.awt.Rectangle;
+import java.awt.Robot;
+import java.awt.Toolkit;
+import java.awt.event.InputEvent;
+import javax.swing.JFrame;
+import javax.swing.JScrollPane;
+import javax.swing.JTree;
+import javax.swing.SwingUtilities;
+import javax.swing.event.TreeExpansionEvent;
+import javax.swing.event.TreeExpansionListener;
+import javax.swing.tree.DefaultMutableTreeNode;
+import javax.swing.tree.DefaultTreeModel;
+import javax.swing.tree.TreeNode;
+import sun.awt.SunToolkit;
+
+public class bug6505523 {
+
+    private static JTree tree;
+
+    public static void main(String[] args) throws Exception {
+        SunToolkit toolkit = (SunToolkit) Toolkit.getDefaultToolkit();
+        Robot robot = new Robot();
+        robot.setAutoDelay(50);
+
+        SwingUtilities.invokeAndWait(new Runnable() {
+
+            @Override
+            public void run() {
+                createAndShowGUI();
+            }
+        });
+
+        toolkit.realSync();
+
+        Point point = getRowPointToClick(2);
+        robot.mouseMove(point.x, point.y);
+        robot.mousePress(InputEvent.BUTTON1_MASK);
+        robot.mouseRelease(InputEvent.BUTTON1_MASK);
+
+        toolkit.realSync();
+
+    }
+
+    private static Point getRowPointToClick(final int row) throws Exception {
+
+        final Point[] result = new Point[1];
+
+        SwingUtilities.invokeAndWait(new Runnable() {
+
+            @Override
+            public void run() {
+                Rectangle rect = tree.getRowBounds(row);
+                Point point = new Point(rect.x - 5, rect.y + rect.height / 2);
+                SwingUtilities.convertPointToScreen(point, tree);
+                result[0] = point;
+            }
+        });
+
+        return result[0];
+    }
+
+    private static void createAndShowGUI() {
+        final DefaultMutableTreeNode root = new DefaultMutableTreeNode("Problem with NPE under JDK 1.6");
+        final DefaultMutableTreeNode problematic = new DefaultMutableTreeNode("Expand me and behold a NPE in stderr");
+        problematic.add(new DefaultMutableTreeNode("some content"));
+        root.add(new DefaultMutableTreeNode("irrelevant..."));
+        root.add(problematic);
+
+        final DefaultTreeModel model = new DefaultTreeModel(root);
+        tree = new JTree(model);
+        tree.setRootVisible(true);
+        tree.setShowsRootHandles(true);
+        tree.expandRow(0);
+        tree.collapseRow(2);
+
+        // this is critical - without dragEnabled everything works
+        tree.setDragEnabled(true);
+
+        tree.addTreeExpansionListener(new TreeExpansionListener() {
+
+            @Override
+            public void treeExpanded(TreeExpansionEvent event) {
+                TreeNode parent = problematic.getParent();
+                if (parent instanceof DefaultMutableTreeNode) {
+                    model.removeNodeFromParent(problematic);
+                }
+            }
+
+            @Override
+            public void treeCollapsed(TreeExpansionEvent event) {
+            }
+        });
+
+        JFrame frame = new JFrame("JTree Problem");
+        frame.add(new JScrollPane(tree));
+        frame.setSize(500, 300);
+        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        frame.setLocationRelativeTo(null);
+        frame.setVisible(true);
+    }
+}
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