6938583: Unexpected NullPointerException by InputContext.endComposition()

Reviewed-by: rupashka
Contributed-by: NCharles Lee <littlee@linux.vnet.ibm.com>

src/share/classes/javax/swing/text/DefaultCaret.java

@@ -403,6 +403,10 @@ public class DefaultCaret extends Rectangle implements Caret, FocusListener, Mou
      * @see MouseListener#mouseClicked
      */
     public void mouseClicked(MouseEvent e) {
+        if (getComponent() == null) {
+            return;
+        }
+
         int nclicks = SwingUtilities2.getAdjustedClickCount(getComponent(), e);
 
         if (! e.isConsumed()) {

test/javax/swing/text/DefaultCaret/6938583/bug6938583.java

+/*
+ * Copyright (c) 2011 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.
+ */
+
+/*
+ * Portions Copyright (c) 2011 IBM Corporation
+ */
+
+/*
+ * @test
+ * @bug 6938583
+ * @summary Unexpected NullPointerException when use CodeIM demo on windows
+ * @author LittleE
+ */
+
+import javax.swing.*;
+import javax.swing.text.DefaultCaret;
+import java.awt.event.MouseEvent;
+
+public class bug6938583 {
+    public static void main(String[] args) throws Exception {
+        SwingUtilities.invokeAndWait(new Runnable() {
+            public void run() {
+                JTextArea jta = new JTextArea();
+                DefaultCaret dc = new DefaultCaret();
+                jta.setCaret(dc);
+                dc.deinstall(jta);
+                dc.mouseClicked(new MouseEvent(jta, MouseEvent.MOUSE_CLICKED, 0, 0, 0, 0, 0, false));
+            }
+        });
+    }
+}