6603771: Nimbus L&F: Ctrl+F7 keybinding for Jinternal Frame throws a NPE.

Reviewed-by: abhiscxk, serb

src/java.desktop/share/classes/javax/swing/plaf/basic/BasicDesktopPaneUI.java

@@ -438,6 +438,9 @@ public class BasicDesktopPaneUI extends DesktopPaneUI {
                 }
                 Insets minOnScreenInsets =
                     UIManager.getInsets("Desktop.minOnScreenInsets");
+                if (minOnScreenInsets == null) {
+                    minOnScreenInsets = new Insets(0, 0, 0, 0);
+                }
                 Dimension size = c.getSize();
                 Dimension minSize = c.getMinimumSize();
                 int dpWidth = dp.getWidth();

test/jdk/javax/swing/JInternalFrame/JInternalFrameTest.java

@@ -0,0 +1,135 @@
+/*
+ * Copyright (c) 2022, 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
+ * @key headful
+ * @bug 6603771
+ * @summary  Verifies Nimbus L&F: Ctrl+F7 keybinding for Jinternal Frame throws a NPE
+ * @run main JInternalFrameTest
+ */
+import java.awt.BorderLayout;
+import java.awt.Dimension;
+import java.awt.EventQueue;
+import java.awt.Point;
+import java.awt.Rectangle;
+import java.awt.Robot;
+import java.awt.event.InputEvent;
+import java.awt.event.KeyEvent;
+import javax.swing.JDesktopPane;
+import javax.swing.JFrame;
+import javax.swing.JInternalFrame;
+import javax.swing.JPanel;
+import javax.swing.SwingUtilities;
+import javax.swing.UIManager;
+import javax.swing.UnsupportedLookAndFeelException;
+
+public class JInternalFrameTest {
+    static JFrame jFrame;
+    static JInternalFrame iFrame;
+    static boolean isAquaLAF;
+    static int controlKey;
+
+    volatile static boolean failed = false;
+
+     private static void setLookAndFeel(UIManager.LookAndFeelInfo laf) {
+        try {
+            UIManager.setLookAndFeel(laf.getClassName());
+        } catch (UnsupportedLookAndFeelException ignored) {
+            System.out.println("Unsupported L&F: " + laf.getClassName());
+        } catch (ClassNotFoundException | InstantiationException
+                | IllegalAccessException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static void main(String[] args) throws Exception {
+        Robot robot = new Robot();
+        EventQueue.invokeAndWait(
+            () -> Thread.currentThread().setUncaughtExceptionHandler(
+                (t, e) -> {
+                    failed = true;
+                }
+        ));
+        for (UIManager.LookAndFeelInfo laf :
+                 UIManager.getInstalledLookAndFeels()) {
+            System.out.println("Testing L&F: " + laf.getClassName());
+            SwingUtilities.invokeAndWait(() -> setLookAndFeel(laf));
+            try {
+                SwingUtilities.invokeAndWait(() -> createUI());
+                robot.waitForIdle();
+                robot.delay(1000);
+
+                Point pt = iFrame.getLocationOnScreen();
+                Rectangle dim = iFrame.getBounds();
+                robot.mouseMove(pt.x + dim.width/3, pt.y+10);
+                robot.waitForIdle();
+                robot.mousePress(InputEvent.BUTTON1_DOWN_MASK);
+                robot.mouseRelease(InputEvent.BUTTON1_DOWN_MASK);
+                robot.waitForIdle();
+                robot.delay(1000);
+                robot.keyPress(KeyEvent.VK_CONTROL);
+                robot.keyPress(KeyEvent.VK_F7);
+                robot.keyRelease(KeyEvent.VK_F7);
+                robot.keyRelease(KeyEvent.VK_CONTROL);
+                robot.waitForIdle();
+                robot.delay(1000);
+                robot.keyPress(KeyEvent.VK_UP);
+                robot.keyRelease(KeyEvent.VK_UP);
+                robot.waitForIdle();
+                robot.delay(1000);
+                if (failed) {
+                    throw new RuntimeException("Exception thrown");
+                }
+            } finally {
+                SwingUtilities.invokeAndWait(() -> {
+                    if (jFrame != null) {
+                        jFrame.dispose();
+                    }
+                });
+            }
+        }
+    }
+
+    private static void createUI() {
+        jFrame = new JFrame();
+
+        JDesktopPane desktopPane = new JDesktopPane();
+
+        iFrame =  new JInternalFrame("Test");
+        iFrame.setTitle("InternalFrame");
+        iFrame.setLocation(50, 50);
+        iFrame.setSize(200, 200);
+        iFrame.setVisible(true);
+
+        desktopPane.add(iFrame);
+
+        JPanel panel = new JPanel();
+        panel.setLayout(new BorderLayout());
+        panel.add(desktopPane, BorderLayout.CENTER);
+
+        jFrame.add(panel, BorderLayout.CENTER);
+        jFrame.setSize(400, 400);
+        jFrame.setLocationRelativeTo(null);
+        jFrame.setVisible(true);
+    }
+}