8289616: Drop use of Thread.stop in AppContext

Reviewed-by: alanb, iris, azvegint

src/java.desktop/share/classes/sun/awt/AppContext.java

@@ -397,6 +397,13 @@ public final class AppContext {
      */
     @SuppressWarnings({"deprecation", "removal"})
     public void dispose() throws IllegalThreadStateException {
+        System.err.println(
+            """
+            WARNING: sun.awt.AppContext.dispose() no longer stops threads.
+            Additionally AppContext will be removed in a future release.
+            Remove all uses of this internal class as soon as possible.
+            There is no replacement.
+            """);
         // Check to be sure that the current Thread isn't in this AppContext
         if (this.threadGroup.parentOf(Thread.currentThread().getThreadGroup())) {
             throw new IllegalThreadStateException(
@@ -502,33 +509,6 @@ public final class AppContext {
             } catch (InterruptedException e) { }
         }
 
-        // Then, we stop any remaining Threads
-        AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
-            Thread[] threads;
-            int len, threadCount;
-            do {
-                len = threadGroup.activeCount() + 4;
-                threads = new Thread[len];
-                threadCount = threadGroup.enumerate(threads);
-            } while (threadCount == len);
-            for (int i = 0; i < threadCount; i++) {
-                threads[i].stop();
-            }
-            return null;
-        });
-
-        // Next, we sleep 10ms at a time, waiting for all of the active
-        // Threads in the ThreadGroup to die.
-
-        startTime = System.currentTimeMillis();
-        endTime = startTime + THREAD_INTERRUPT_TIMEOUT;
-        while ((this.threadGroup.activeCount() > 0) &&
-               (System.currentTimeMillis() < endTime)) {
-            try {
-                Thread.sleep(10);
-            } catch (InterruptedException e) { }
-        }
-
         // Next, we remove this and all subThreadGroups from threadGroup2appContext
         int numSubGroups = this.threadGroup.activeGroupCount();
         if (numSubGroups > 0) {
@@ -542,13 +522,6 @@ public final class AppContext {
 
         threadAppContext.set(null);
 
-        // Finally, we destroy the ThreadGroup entirely.
-        try {
-            this.threadGroup.destroy();
-        } catch (IllegalThreadStateException e) {
-            // Fired if not all the Threads died, ignore it and proceed
-        }
-
         synchronized (table) {
             this.table.clear(); // Clear out the Hashtable to ease garbage collection
         }

test/jdk/java/awt/AppContext/ApplicationThreadsStop/ApplicationThreadsStop.java

@@ -1,77 +0,0 @@
-/*
- * Copyright (c) 2015, 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.AWTException;
-import java.awt.Frame;
-import java.awt.Robot;
-
-import sun.awt.AppContext;
-import sun.awt.SunToolkit;
-
-/**
- * @test
- * @key headful
- * @bug 8136858
- * @modules java.desktop/sun.awt
- * @run main/othervm/java.security.policy=java.policy -Djava.security.manager ApplicationThreadsStop
- */
-public final class ApplicationThreadsStop implements Runnable {
-
-    private static AppContext contextToDispose;
-    private static Thread thread;
-
-    public static void main(final String[] args) throws Exception {
-        ThreadGroup tg = new ThreadGroup("TestThreadGroup");
-        Thread t = new Thread(tg, new ApplicationThreadsStop());
-        t.start();
-        t.join();
-        contextToDispose.dispose();
-        // wait for appcontext to be destroyed
-        Thread.sleep(10000);
-        if(thread.isAlive()){
-            throw new RuntimeException("Thread is alive");
-        }
-    }
-
-    @Override
-    public void run() {
-        contextToDispose = SunToolkit.createNewAppContext();
-        Frame f = new Frame();
-        f.setSize(300, 300);
-        f.setLocationRelativeTo(null);
-        f.setVisible(true);
-        thread = new Thread(() -> {
-            while(true);
-        });
-        thread.start();
-        sync();
-    }
-
-    private static void sync() {
-        try {
-            new Robot().waitForIdle();
-        } catch (AWTException e) {
-            throw new RuntimeException(e);
-        }
-    }
-}