8256643: Terminally deprecate ThreadGroup stop, destroy, isDestroyed, setDaemon and isDaemon

Reviewed-by: serb, rriggs, iris, mchung, smarks

src/java.base/share/classes/java/lang/ThreadGroup.java

@@ -185,7 +185,13 @@ public class ThreadGroup implements Thread.UncaughtExceptionHandler {
      * @return  {@code true} if this thread group is a daemon thread group;
      *          {@code false} otherwise.
      * @since   1.0
+     *
+     * @deprecated The API and mechanism for destroying a ThreadGroup is inherently
+     *             flawed. The ability to explicitly or automatically destroy a
+     *             thread group, and the concept of daemon thread group, will be
+     *             removed in a future release.
      */
+    @Deprecated(since="16", forRemoval=true)
     public final boolean isDaemon() {
         return daemon;
     }
@@ -195,7 +201,12 @@ public class ThreadGroup implements Thread.UncaughtExceptionHandler {
      *
      * @return  true if this object is destroyed
      * @since   1.1
+     *
+     * @deprecated The API and mechanism for destroying a ThreadGroup is inherently
+     *             flawed. The ability to explicitly or automatically destroy a
+     *             thread group will be removed in a future release.
      */
+    @Deprecated(since="16", forRemoval=true)
     public synchronized boolean isDestroyed() {
         return destroyed;
     }
@@ -217,7 +228,13 @@ public class ThreadGroup implements Thread.UncaughtExceptionHandler {
      * @see        java.lang.SecurityException
      * @see        java.lang.ThreadGroup#checkAccess()
      * @since      1.0
+     *
+     * @deprecated The API and mechanism for destroying a ThreadGroup is inherently
+     *             flawed. The ability to explicitly or automatically destroy a
+     *             thread group, and the concept of daemon thread group, will be
+     *             removed in a future release.
      */
+    @Deprecated(since="16", forRemoval=true)
     public final void setDaemon(boolean daemon) {
         checkAccess();
         this.daemon = daemon;
@@ -602,7 +619,7 @@ public class ThreadGroup implements Thread.UncaughtExceptionHandler {
      * @deprecated    This method is inherently unsafe.  See
      *     {@link Thread#stop} for details.
      */
-    @Deprecated(since="1.2")
+    @Deprecated(since="1.2", forRemoval=true)
     public final void stop() {
         if (stopOrSuspend(false))
             Thread.currentThread().stop();
@@ -763,7 +780,12 @@ public class ThreadGroup implements Thread.UncaughtExceptionHandler {
      *               thread group.
      * @see        java.lang.ThreadGroup#checkAccess()
      * @since      1.0
+     *
+     * @deprecated The API and mechanism for destroying a ThreadGroup is inherently
+     *             flawed. The ability to explicitly or automatically destroy a
+     *             thread group will be removed in a future release.
      */
+    @Deprecated(since="16", forRemoval=true)
     public final void destroy() {
         int ngroupsSnapshot;
         ThreadGroup[] groupsSnapshot;

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

@@ -1105,6 +1105,7 @@ public class EventQueue {
         }
     }
 
+    @SuppressWarnings({"deprecation", "removal"})
     final void initDispatchThread() {
         pushPopLock.lock();
         try {

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

@@ -392,7 +392,7 @@ public final class AppContext {
      *                                    contained within this AppContext
      * @since      1.2
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings({"deprecation", "removal"})
     public void dispose() throws IllegalThreadStateException {
         // Check to be sure that the current Thread isn't in this AppContext
         if (this.threadGroup.parentOf(Thread.currentThread().getThreadGroup())) {

src/jdk.jshell/share/classes/jdk/jshell/execution/LocalExecutionControl.java

@@ -124,7 +124,7 @@ public class LocalExecutionControl extends DirectExecutionControl {
     }
 
     @Override
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings({"deprecation", "removal"})
     public void stop() throws EngineTerminationException, InternalException {
         synchronized (STOP_LOCK) {
             if (!userCodeRunning) {