8267961: JInternalFrame.getNormalBounds() returns normalBounds when maximized state is false instead of bounds

Reviewed-by: tr, dnguyen

src/java.desktop/share/classes/javax/swing/JInternalFrame.java

@@ -987,6 +987,9 @@ public class JInternalFrame extends JComponent implements
             = "Indicates whether this internal frame is maximized.")
     public void setMaximum(boolean b) throws PropertyVetoException {
         if (isMaximum == b) {
+            if (!b) {
+                normalBounds = null;
+            }
             return;
         }
 
@@ -998,6 +1001,9 @@ public class JInternalFrame extends JComponent implements
            get it wrong... See, for example, getNormalBounds() */
         isMaximum = b;
         firePropertyChange(IS_MAXIMUM_PROPERTY, oldValue, newValue);
+        if (!b) {
+            normalBounds = null;
+        }
     }
 
     /**

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

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2026, 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 8267961
+  * @summary Verify JInternalFrame.getNormalBounds()
+  *          returns getBounds() value in non-maximized state
+  * @run main TestNonMaximizedNormalBounds
+  */
+
+import java.awt.Rectangle;
+import javax.swing.JDesktopPane;
+import javax.swing.JInternalFrame;
+import javax.swing.SwingUtilities;
+import java.beans.PropertyVetoException;
+
+public class TestNonMaximizedNormalBounds {
+
+    private static volatile Rectangle bounds;
+    private static volatile Rectangle normalBounds;
+    private static JInternalFrame jif;
+
+    public static void main(String[] args) throws Exception {
+        SwingUtilities.invokeAndWait(() -> {
+            Rectangle bounds = new Rectangle(96, 97, 98, 99);
+            Rectangle nbounds = new Rectangle(196, 197, 198, 199);
+            JDesktopPane p = new JDesktopPane();
+            jif = new JInternalFrame();
+            p.add(jif);
+            jif.setBounds(bounds);
+            jif.setNormalBounds(nbounds);
+        });
+        Thread.sleep(100);
+        SwingUtilities.invokeAndWait(() -> {
+            try {
+                jif.setMaximum(false);
+            } catch (PropertyVetoException e) {
+                throw new RuntimeException(e);
+            }
+        });
+        Thread.sleep(100);
+        SwingUtilities.invokeAndWait(() -> {
+            normalBounds = jif.getNormalBounds();
+            bounds = jif.getBounds();
+        });
+        if (!normalBounds.equals(bounds)) {
+            System.out.println("normalBounds " + normalBounds + " getBounds " + bounds);
+            throw new RuntimeException("normalBounds not equal to getBounds in non-maximized state");
+        }
+    }
+}