6919529: NPE from MultiUIDefaults.getUIError

Reviewed-by: aghaisas, psadhukhan, serb

jdk/src/java.desktop/share/classes/javax/swing/MultiUIDefaults.java

@@ -127,7 +127,7 @@ class MultiUIDefaults extends UIDefaults
 
     @Override
     protected void getUIError(String msg) {
-        if (tables.length > 0) {
+        if (tables != null && tables.length > 0 && tables[0] != null) {
             tables[0].getUIError(msg);
         } else {
             super.getUIError(msg);

jdk/test/javax/swing/MultiUIDefaults/NPECheck/MultiUIDefaultsNPECheck.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2017, 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 6919529
+ * @summary Checks if there is a null pointer exception when the component UI
+ *   is null.
+ * @run main MultiUIDefaultsNPECheck
+ */
+import javax.swing.LookAndFeel;
+import javax.swing.JLabel;
+import javax.swing.UIManager;
+import javax.swing.UnsupportedLookAndFeelException;
+import javax.swing.UIDefaults;
+import javax.swing.SwingUtilities;
+
+public class MultiUIDefaultsNPECheck {
+    public static void main(String[] args) throws Exception {
+        SwingUtilities.invokeAndWait(() -> {
+            Test();
+        });
+    }
+
+    public static void Test() {
+        JLabel label = new JLabel();
+
+        try {
+            UIManager.setLookAndFeel(new LookAndFeel() {
+                @Override
+                public String getName() {
+                    return null;
+                }
+
+                @Override
+                public String getID() {
+                    return null;
+                }
+
+                @Override
+                public String getDescription() {
+                    return null;
+                }
+
+                @Override
+                public boolean isNativeLookAndFeel() {
+                    return false;
+                }
+
+                @Override
+                public boolean isSupportedLookAndFeel() {
+                    return true;
+                }
+
+                @Override
+                public UIDefaults getDefaults() {
+                    return null;
+                }
+            });
+        }  catch (UnsupportedLookAndFeelException e) {
+            System.err.println("Warning: test not applicable because of " +
+                "unsupported look and feel");
+            return;
+        }
+
+        try {
+            UIManager.getDefaults().getUI(label);
+        } catch (NullPointerException e) {
+            throw new RuntimeException("Got null pointer exception. Hence " +
+                    "Test Failed");
+        }
+    }
+}