8359266: Delete the usage of AppContext in the GraphicsDevice

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2025, 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
@@ -27,7 +27,6 @@
 
 import java.awt.image.ColorModel;
 
-import sun.awt.AppContext;
 import sun.awt.SunToolkit;
 
 /**
@@ -75,13 +74,7 @@
  */
 public abstract class GraphicsDevice {
 
-    private Window fullScreenWindow;
-    private AppContext fullScreenAppContext; // tracks which AppContext
-                                             // created the FS window
-    // this lock is used for making synchronous changes to the AppContext's
-    // current full screen window
-    private final Object fsAppContextLock = new Object();
-
+    private volatile Window fullScreenWindow;
     private Rectangle windowedModeBounds;
 
     /**
@@ -303,23 +296,15 @@ public void setFullScreenWindow(Window w) {
             fullScreenWindow.setBounds(windowedModeBounds);
         }
         // Set the full screen window
-        synchronized (fsAppContextLock) {
-            // Associate fullscreen window with current AppContext
-            if (w == null) {
-                fullScreenAppContext = null;
-            } else {
-                fullScreenAppContext = AppContext.getAppContext();
-            }
-            fullScreenWindow = w;
-        }
+        fullScreenWindow = w;
         if (fullScreenWindow != null) {
             windowedModeBounds = fullScreenWindow.getBounds();
             // Note that we use the graphics configuration of the device,
             // not the window's, because we're setting the fs window for
             // this device.
             final GraphicsConfiguration gc = getDefaultConfiguration();
             final Rectangle screenBounds = gc.getBounds();
-            if (SunToolkit.isDispatchThreadForAppContext(fullScreenWindow)) {
+            if (EventQueue.isDispatchThread()) {
                 // Update graphics configuration here directly and do not wait
                 // asynchronous notification from the peer. Note that
                 // setBounds() will reset a GC, if it was set incorrectly.
@@ -342,15 +327,7 @@ public void setFullScreenWindow(Window w) {
      * @since 1.4
      */
     public Window getFullScreenWindow() {
-        Window returnWindow = null;
-        synchronized (fsAppContextLock) {
-            // Only return a handle to the current fs window if we are in the
-            // same AppContext that set the fs window
-            if (fullScreenAppContext == AppContext.getAppContext()) {
-                returnWindow = fullScreenWindow;
-            }
-        }
-        return returnWindow;
+        return fullScreenWindow;
     }
 
     /**

test/jdk/java/awt/GraphicsDevice/FullScreenWindowRace.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright Amazon.com Inc. 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.GraphicsDevice;
+import java.awt.GraphicsEnvironment;
+import java.awt.Window;
+
+/**
+ * @test
+ * @key headful
+ * @bug 8359266
+ * @summary Tests for a race condition when setting a full-screen window
+ */
+public final class FullScreenWindowRace {
+
+    public static void main(String[] args) throws InterruptedException {
+        Window window = new Window(null);
+        GraphicsDevice gd = GraphicsEnvironment.getLocalGraphicsEnvironment()
+                                               .getDefaultScreenDevice();
+
+        Thread thread = new Thread(() -> {
+            while (gd.getFullScreenWindow() == null) {
+                // Busy wait - can be optimized away without volatile
+            }
+        });
+
+        thread.setDaemon(true);
+        thread.start();
+
+        // Give thread some time to start and begin the loop
+        Thread.sleep(2000);
+
+        gd.setFullScreenWindow(window);
+
+        thread.join(15000);
+
+        boolean alive = thread.isAlive();
+
+        gd.setFullScreenWindow(null);
+        window.dispose();
+        if (alive) {
+            throw new RuntimeException("Full screen window is NOT detected!");
+        }
+    }
+}