6278172: TextComponent.getSelectedText() throws StringIndexOutOfBoundsException

Reviewed-by: aivanov

src/java.desktop/share/classes/java/awt/TextComponent.java

@@ -240,21 +240,18 @@ public class TextComponent extends Component implements Accessible {
      * @see         java.awt.TextComponent#getText
      */
     public synchronized void setText(String t) {
-        if (t == null) {
-            t = "";
-        }
-        TextComponentPeer peer = (TextComponentPeer)this.peer;
-        if (peer != null) {
-            text = peer.getText();
+        text = (t != null) ? t : "";
+        int selectionStart = getSelectionStart();
+        int selectionEnd = getSelectionEnd();
+        TextComponentPeer peer = (TextComponentPeer) this.peer;
+        if (peer != null && !text.equals(peer.getText())) {
             // Please note that we do not want to post an event
             // if TextArea.setText() or TextField.setText() replaces text
             // by same text, that is, if component's text remains unchanged.
-            if (!t.equals(text)) {
-                text = t;
-                peer.setText(text);
-            }
-        } else {
-            text = t;
+            peer.setText(text);
+        }
+        if (selectionStart != selectionEnd) {
+            select(selectionStart, selectionEnd);
         }
     }
 

test/jdk/java/awt/TextComponent/SetTextSelection.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2020, 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.awt.Frame;
+import java.awt.TextArea;
+import java.awt.TextComponent;
+import java.awt.TextField;
+
+/**
+ * @test
+ * @key headful
+ * @bug 6278172
+ * @summary Tests that TextComponent#setText() preserves the selection
+ */
+public final class SetTextSelection {
+
+    private static final String LONG_TEXT = "text field";
+    private static final String SHORT_TEXT = "text";
+
+    public static void main(String[] args) {
+        testNoFrame(true);
+        testNoFrame(false);
+        for (int i = 0; i < 5; i++) {
+            testFrame(true, i);
+            testFrame(false, i);
+        }
+        testDisposedFrame(true);
+        testDisposedFrame(false);
+    }
+
+    private static void testNoFrame(boolean field) {
+        TextComponent tf = field ? new TextField(LONG_TEXT) :
+                                   new TextArea(LONG_TEXT);
+        tf.selectAll();
+        tf.setText(SHORT_TEXT);
+        test(tf);
+    }
+
+    private static void testDisposedFrame(boolean field) {
+        Frame frame = new Frame();
+        try {
+            TextComponent tf = field ? new TextField(LONG_TEXT) :
+                                       new TextArea(LONG_TEXT);
+            frame.add(tf);
+            frame.pack();
+            tf.selectAll();
+            frame.dispose();
+            tf.setText(SHORT_TEXT);
+            test(tf);
+        } finally {
+            frame.dispose();
+        }
+    }
+
+    private static void testFrame(boolean field, int step) {
+        Frame frame = new Frame();
+        try {
+            TextComponent tf = field ? new TextField(LONG_TEXT) :
+                                       new TextArea(LONG_TEXT);
+            if (step == 1) {
+                frame.pack();
+            }
+            frame.add(tf);
+            if (step == 2) {
+                frame.pack();
+            }
+            tf.selectAll();
+            if (step == 3) {
+                frame.pack();
+            }
+            tf.setText(SHORT_TEXT);
+            if (step == 4) {
+                frame.pack();
+            }
+            test(tf);
+        } finally {
+            frame.dispose();
+        }
+    }
+
+    private static void test(TextComponent tf) {
+        String str = tf.getSelectedText();
+        if (!str.equals(SHORT_TEXT)) {
+            throw new RuntimeException(str);
+        }
+    }
+}