src/java.naming/share/classes/com/sun/jndi/ldap/EventSupport.java

*** 1,7 ****
  /*
!  * Copyright (c) 1999, 2019, 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) 1999, 2020, 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
*** 248,259 ****
--- 248,264 ----
        */
      synchronized void removeDeadNotifier(NotifierArgs info) {
          if (debug) {
              System.err.println("EventSupport.removeDeadNotifier: " + info.name);
          }
+         if (notifiers != null) {
+             // Only do this if cleanup() not been triggered, otherwise here
+             // will throw NullPointerException since notifiers will be set to
+             // null in cleanup()
              notifiers.remove(info);
          }
+     }
  
      /**
       * Fire an event to unsolicited listeners.
       * package private;
       * Called by LdapCtx when its clnt receives an unsolicited notification.
*** 327,336 ****
--- 332,346 ----
       * them to the registered listeners.
       * Package private; used by NamingEventNotifier to fire events
       */
      synchronized void queueEvent(EventObject event,
                                   Vector<? extends NamingListener> vector) {
+         if (notifiers == null) {
+             // That means cleanup() already done, not queue event anymore,
+             // otherwise, new created EventQueue will not been cleanup.
+             return;
+         }
          if (eventQueue == null)
              eventQueue = new EventQueue();
  
          /*
           * Copy the vector in order to freeze the state of the set