[DIRMINA-1047] NullPointerException in AbstractIoSession.destroy()

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.15
• Fix Version/s: 2.0.16
• Component/s: Core
• Environment: Any
• Assignee: Unassigned
• Reporter: Carl Wicklow
• Created: 07/Oct/16 07:45
• Updated: 20/Oct/16 20:10
• Resolved: 13/Oct/16 08:16

Description

After upgrading to v2.0.15, we get this NPE ...

java.lang.NullPointerException
	at org.apache.mina.core.session.AbstractIoSession.destroy(AbstractIoSession.java:369)
	at org.apache.mina.core.session.AbstractIoSession.closeNow(AbstractIoSession.java:350)
	at org.apache.mina.core.session.DefaultIoSessionDataStructureFactory$DefaultWriteRequestQueue.poll(DefaultIoSessionDataStructureFactory.java:222)
	at org.apache.mina.core.polling.AbstractPollingIoProcessor.flushNow(AbstractPollingIoProcessor.java:827)
	at org.apache.mina.core.polling.AbstractPollingIoProcessor.flush(AbstractPollingIoProcessor.java:767)
	at org.apache.mina.core.polling.AbstractPollingIoProcessor.access$700(AbstractPollingIoProcessor.java:68)
	at org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:1125)
	at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:64)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

If I'm reading it right, the destroy also needs to allow that the writeRequest returned by the poll() of the WriteRequestQueue may return null if the queue is empty.

In our case the destroy was invoked after polling a CLOSE_REQUEST caused by an earlier closeOnFlush(), and the write request queue was empty.

AbstractIoSession.java

    protected void destroy() {
        if (writeRequestQueue != null) {
            while (!writeRequestQueue.isEmpty(this)) {
                WriteRequest writeRequest = writeRequestQueue.poll(this);
                WriteFuture writeFuture = writeRequest.getFuture();
                
                // The WriteRequest may not always have a future : The CLOSE_REQUEST
                // and MESSAGE_SENT_REQUEST don't.
                if (writeFuture != null) {
                    writeFuture.setWritten();
                }
            }
        }
    }

Issue Links

• is duplicated by: DIRMINA-1050 NullPointerException after upgrade to mina 2.0.15