8076249: NPE in AccessBridge while editing JList model

Reviewed-by: serb, prr, alexsch

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

@@ -3395,15 +3395,18 @@ public class JList<E> extends JComponent implements Scrollable, Accessible
             }
 
             public AccessibleSelection getAccessibleSelection() {
-                return getCurrentAccessibleContext().getAccessibleSelection();
+                AccessibleContext ac = getCurrentAccessibleContext();
+                return ac != null ? ac.getAccessibleSelection() : null;
             }
 
             public AccessibleText getAccessibleText() {
-                return getCurrentAccessibleContext().getAccessibleText();
+                AccessibleContext ac = getCurrentAccessibleContext();
+                return ac != null ? ac.getAccessibleText() : null;
             }
 
             public AccessibleValue getAccessibleValue() {
-                return getCurrentAccessibleContext().getAccessibleValue();
+                AccessibleContext ac = getCurrentAccessibleContext();
+                return ac != null ? ac.getAccessibleValue() : null;
             }
 
 

jdk/test/javax/accessibility/JList/AccessibleJListChildNPETest.java

@@ -0,0 +1,103 @@
+/*
+* 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.
+*/
+
+import java.lang.reflect.InvocationTargetException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import javax.accessibility.Accessible;
+import javax.accessibility.AccessibleContext;
+import javax.swing.AbstractListModel;
+import javax.swing.JFrame;
+import javax.swing.JList;
+import javax.swing.SwingUtilities;
+import javax.swing.WindowConstants;
+
+/* @test
+   @bug 8076249
+   @summary  NPE in AccessBridge while editing JList model
+   @author Mikhail Cherkasov
+   @run main AccessibleJListChildNPETest
+*/
+public class AccessibleJListChildNPETest {
+
+    private static String[] model = { "1", "2", "3", "4", "5", "6" };
+    private static JList<String> list;
+
+    public static void main(String[] args) throws InvocationTargetException, InterruptedException {
+        SwingUtilities.invokeAndWait(new Runnable() {
+            @Override
+            public void run() {
+                JFrame frame = new JFrame();
+                frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
+                final MyModel dataModel = new MyModel(Arrays.asList(model));
+                list = new JList<>(dataModel);
+                frame.getContentPane().add(list);
+                frame.pack();
+                frame.setVisible(true);
+
+            }
+        });
+
+        SwingUtilities.invokeAndWait(new Runnable() {
+            @Override
+            public void run() {
+                AccessibleContext ac = list.getAccessibleContext();
+                MyModel model = (MyModel)list.getModel();
+                Accessible accessibleChild = ac.getAccessibleChild(model.getSize()-1);
+                model.removeFirst();
+                accessibleChild.getAccessibleContext().getAccessibleSelection();
+                accessibleChild.getAccessibleContext().getAccessibleText();
+                accessibleChild.getAccessibleContext().getAccessibleValue();
+            }
+        });
+    }
+
+    protected static class MyModel extends AbstractListModel<String> {
+        private List<String> items = new ArrayList<>();
+
+        MyModel(final List<String> newItems) {
+            super();
+            items.addAll(newItems);
+            fireIntervalAdded(this, 0, getSize() - 1);
+        }
+
+        void removeFirst() {
+            if(getSize() > 0) {
+                items.remove(0);
+                fireIntervalRemoved(this, 0, 0);
+            }
+        }
+
+        @Override
+        public int getSize() {
+            return items.size();
+        }
+
+        @Override
+        public String getElementAt(int index) {
+            return items.get(index);
+        }
+    }
+}