src/java.desktop/unix/native/libawt_xawt/awt/awt_util.c

*** 1,7 ****
  /*
!  * Copyright (c) 1995, 2014, 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.  Oracle designates this
--- 1,7 ----
  /*
!  * Copyright (c) 1995, 2016, 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.  Oracle designates this
*** 63,101 ****
  
  jboolean
  awtJNI_ThreadYield(JNIEnv *env) {
  
      static jclass threadClass = NULL;
!     static jmethodID yieldMethodID = NULL;
  
!     /* Initialize our java identifiers once. Checking before locking
!      * is a huge performance win.
       */
!     if (threadClass == NULL) {
!         // should enter a monitor here...
!         Boolean err = FALSE;
!         if (threadClass == NULL) {
              jclass tc = (*env)->FindClass(env, "java/lang/Thread");
              CHECK_NULL_RETURN(tc, JNI_FALSE);
              threadClass = (*env)->NewGlobalRef(env, tc);
              (*env)->DeleteLocalRef(env, tc);
              if (threadClass != NULL) {
!                 yieldMethodID = (*env)->GetStaticMethodID(env,
!                                               threadClass,
!                                               "yield",
!                                               "()V"
!                                                 );
              }
          }
          if (yieldMethodID == NULL) {
              threadClass = NULL;
-             err = TRUE;
-         }
-         if (err) {
              return JNI_FALSE;
          }
!     } /* threadClass == NULL*/
  
      (*env)->CallStaticVoidMethod(env, threadClass, yieldMethodID);
      DASSERT(!((*env)->ExceptionOccurred(env)));
      if ((*env)->ExceptionCheck(env)) {
          return JNI_FALSE;
--- 63,97 ----
  
  jboolean
  awtJNI_ThreadYield(JNIEnv *env) {
  
      static jclass threadClass = NULL;
!     static volatile jmethodID yieldMethodID = NULL;
  
!     /* Double Check Locking is used with volatile yieldMethodID identifier
!      * to initialize java identifiers only once & multi-thread safe.
       */
! 
!     if (yieldMethodID == NULL) {
!         AWT_LOCK();
!         if (yieldMethodID == NULL) {
              jclass tc = (*env)->FindClass(env, "java/lang/Thread");
              CHECK_NULL_RETURN(tc, JNI_FALSE);
              threadClass = (*env)->NewGlobalRef(env, tc);
+ 
              (*env)->DeleteLocalRef(env, tc);
              if (threadClass != NULL) {
!                 yieldMethodID = (*env)->GetStaticMethodID(env, threadClass,
!                                               "yield", "()V");
              }
          }
+         AWT_UNLOCK();
          if (yieldMethodID == NULL) {
              threadClass = NULL;
              return JNI_FALSE;
          }
!     }
  
      (*env)->CallStaticVoidMethod(env, threadClass, yieldMethodID);
      DASSERT(!((*env)->ExceptionOccurred(env)));
      if ((*env)->ExceptionCheck(env)) {
          return JNI_FALSE;