[FLEX-34978] Shutdown errors when running Blazed DS inside of Tomcat & Java 8.

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: BlazeDS 4.7
• Component/s: .Unspecified - Framework
• Environment: Tomcat 7.0.58; Java 8
• Flags: Important
• Assignee: Unassigned
• Reporter: Douglas Yeager
• Created: 30/Nov/15 15:50
• Updated: 25/Jan/18 14:52

Description

Inside flex.messaging.FlexSessionManager a ConcurrentHashMap member variable is declared and later the keySet() is accessed. The ConcurrentHashMap interface has changed between Java 7 and Java 8. So although it will work when running with Java 7; it will break if you run with Java 8. It should be updated to declare the member as just a Map or ConcurrentMap (which is done elsewhere in the BlazeDS source); however, in the FlexSessionManager it is declared as:
private final ConcurrentHashMap<Class<? extends FlexSession>, AbstractFlexSessionProvider> providers = new ConcurrentHashMap<Class<? extends FlexSession>, AbstractFlexSessionProvider>();

Then in the FlexSessionManager.stop() implementation it performs the following directly off of the ConcurrentHashMap which results in a failure:
/**

• Stops the <tt>FlexSessionManager</tt>.
• Any registered <tt>FlexSession</tt> providers are stopped and unregistered.
  */
  @Override
  public void stop()
  {
  if (!isStarted())
  return;

super.stop();

for (Class<? extends FlexSession> sessionClass : providers.keySet())

{ unregisterFlexSessionProvider(sessionClass); }

providers.clear();
}

The following is the stacktrace seen in the error log on shutdown:
2015-11-25 13:47:01,804 [localhost-startStop-2] ERROR org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/context] - Servlet MessageBrokerServlet threw unload() exception
javax.servlet.ServletException: Servlet.destroy() for servlet MessageBrokerServlet threw exception
at org.apache.catalina.core.StandardWrapper.unload(StandardWrapper.java:1507)
at org.apache.catalina.core.StandardWrapper.stopInternal(StandardWrapper.java:1847)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232)
at org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5707)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232)
at org.apache.catalina.core.ContainerBase$StopChild.call(ContainerBase.java:1591)
at org.apache.catalina.core.ContainerBase$StopChild.call(ContainerBase.java:1580)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NoSuchMethodError: java.util.concurrent.ConcurrentHashMap.keySet()Ljava/util/concurrent/ConcurrentHashMap$KeySetView;
at flex.messaging.FlexSessionManager.stop(FlexSessionManager.java:293)
at flex.messaging.MessageBroker.stop(MessageBroker.java:380)
at flex.messaging.MessageBrokerServlet.destroy(MessageBrokerServlet.java:263)
at org.apache.catalina.core.StandardWrapper.unload(StandardWrapper.java:1486)
... 10 more

There are two other classes that declare ConcurrentHashMap in the code that should be cleaned up too (although keySet() is not referenced in those classes , it would be better to address them to ensure this issue doesn't re-occur):
flex.messaging.endpoints.BaseStreamingHTTPEndpoint
flex.messaging.MessageBroker