IT37224: java.lang.NullPointerException thrown when multiple threads connecting to the QMGR concurrently

APAR status

• Closed as program error.

Error description

• A MQ classes for JMS v8.0.0.10 application is running inside the
  Hitachi Cosminexus application server on the Linux (x86-64)
  platform, using the Hitachi JVM.
  
  Multiple threads attempt to connect to a z/OS queue manager
  concurrently, where the queue manager is running in the CCSID
  1399.
  
  Occasionally when these threads initially attempt to connect,
  the following NullPointerException is thrown and the connection
  attempt fails:
  
  java.lang.NullPointerException
  at java.util.TreeMap.deleteEntry(TreeMap.java:2340)
  at java.util.TreeMap.remove(TreeMap.java:608)
  at
  com.ibm.mq.jmqi.system.JmqiCodepage$JmqiCodepageFactory.initiali
  zeCodepage(JmqiCodepage.java:307)
  at
  com.ibm.mq.jmqi.system.JmqiCodepage$JmqiCodepageFactory.getByCcs
  id(JmqiCodepage.java:189)
  at
  com.ibm.mq.jmqi.system.JmqiCodepage.getJmqiCodepage(JmqiCodepage
  .java:720)
  at
  com.ibm.mq.jmqi.system.JmqiCodepage.getJmqiCodepage(JmqiCodepage
  .java:682)
  at
  com.ibm.mq.jmqi.remote.impl.RemoteConnection.initSess(RemoteConn
  ection.java:1476)
  at
  com.ibm.mq.jmqi.remote.impl.RemoteConnection.connect(RemoteConne
  ction.java:1007)
  at
  com.ibm.mq.jmqi.remote.impl.RemoteConnectionSpecification.getSes
  sionFromNewConnection(RemoteConnectionSpecification.java:409)
  at
  com.ibm.mq.jmqi.remote.impl.RemoteConnectionSpecification.getSes
  sion(RemoteConnectionSpecification.java:305)
  at
  com.ibm.mq.jmqi.remote.impl.RemoteConnectionPool.getSession(Remo
  teConnectionPool.java:155)
  at
  com.ibm.mq.jmqi.remote.api.RemoteFAP.jmqiConnect(RemoteFAP.java:
  1724)
  at
  com.ibm.mq.jmqi.remote.api.RemoteFAP.jmqiConnect(RemoteFAP.java:
  1288)
  at
  com.ibm.mq.ese.jmqi.InterceptedJmqiImpl.jmqiConnect(InterceptedJ
  mqiImpl.java:376)
  at com.ibm.mq.ese.jmqi.ESEJMQI.jmqiConnect(ESEJMQI.java:560)
  at
  com.ibm.msg.client.wmq.internal.WMQConnection.<init>(WMQConnecti
  on.java:356)
  at
  com.ibm.msg.client.wmq.internal.WMQXAConnection.<init>(WMQXAConn
  ection.java:67)
  at
  com.ibm.msg.client.wmq.factories.WMQXAConnectionFactory.createV7
  ProviderConnection(WMQXAConnectionFactory.java:188)
  at
  com.ibm.msg.client.wmq.factories.WMQConnectionFactory.createProv
  iderConnection(WMQConnectionFactory.java:7913)
  at
  com.ibm.msg.client.wmq.factories.WMQXAConnectionFactory.createPr
  oviderXAConnection(WMQXAConnectionFactory.java:98)
  at
  com.ibm.msg.client.jms.admin.JmsConnectionFactoryImpl.createXACo
  nnectionInternal(JmsConnectionFactoryImpl.java:347)
  at
  com.ibm.mq.jms.MQXAQueueConnectionFactory.createXAQueueConnectio
  n(MQXAQueueConnectionFactory.java:168)
  at
  com.ibm.mq.jms.MQXAQueueConnectionFactory.createXAConnection(MQX
  AQueueConnectionFactory.java:116)
  at
  com.ibm.mq.connector.ConnectionBuilder.createConnection(Connecti
  onBuilder.java:195)
  at
  com.ibm.mq.connector.outbound.ManagedQueueConnectionFactoryImpl.
  createConnection(ManagedQueueConnectionFactoryImpl.java:197)
  at
  com.ibm.mq.connector.outbound.ManagedConnectionImpl.<init>(Manag
  edConnectionImpl.java:173)
  at
  com.ibm.mq.connector.outbound.ManagedQueueConnectionImpl.<init>(
  ManagedQueueConnectionImpl.java:74)
  at
  com.ibm.mq.connector.outbound.ManagedQueueConnectionFactoryImpl.
  createManagedConnection(ManagedQueueConnectionFactoryImpl.java:1
  51)
  at
  com.hitachi.software.ejb.cm.connector.ConnectorResourceFactory.c
  reate(ConnectorResourceFactory.java:338)
  ... ... ...
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  User of the MQ classes for Java/JMS, including users of the MQ
  Managed File Transfer.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When the MQ classes for Java/JMS connects to a queue manager, it
  negotiates a common communication protocol between the queue
  manager and the MQ classes for Java/JMS.
  
  Part of this negotiation includes determining if the JVM has
  Charset support for the Coded Character Set Identifier (CCSID)
  that the queue manager is running in.
  
  The MQ classes for Java/JMS uses a class named:
  
    com.ibm.mq.jmqi.system.JmqiCodepage.getJmqiCodepage
  
  to determine if the JVM has support for a specific CCSID.  This
  class contains two objects of the type:
  
    java.util.TreeMap
  
  which permit the mapping between IBM CCSID integer values, and
  Java java.nio.charset.Charset names.
  
  If the JVM does not have support for the requested Charset, then
  the MQ classes for Java/JMS optimises future requests for
  Charset support by removing these mappings from the TreeMap set.
  
  
  However, if multiple application threads were connecting to the
  queue manager in parallel and the CCSID was not supported by the
  JVM, then it was possible that more than one thread would try
  and remove the entry concurrently, leading to a
  java.lang.NullPointerException to be thrown by the JVM, with a
  stack of the form:
  
  java.lang.NullPointerException
  at java.util.TreeMap.deleteEntry
  at java.util.TreeMap.remove
  at
  com.ibm.mq.jmqi.system.JmqiCodepage$JmqiCodepageFactory.initiali
  zeCodepage
  at
  com.ibm.mq.jmqi.system.JmqiCodepage$JmqiCodepageFactory.getByCcs
  id
  at com.ibm.mq.jmqi.system.JmqiCodepage.getJmqiCodepage
  at com.ibm.mq.jmqi.system.JmqiCodepage.getJmqiCodepage
  
  
  In order to encounter this problem, you require an environment
  where:
  
  (a) The queue manager's CCSID is not supported by the JVM
  (b) Multiple application threads are connecting to the queue
  manager concurrently
  

Problem conclusion

• The MQ classes for Java/JMS has been updated to add Java locking
  around the updating of the java.util.TreeMap object to ensure
  that this issue no longer occurs.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.0 LTS   9.0.0.12
  v9.1 LTS   9.1.0.9
  v9.2 LTS   9.2.0.4
  v9.x CD    9.2.4
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  IBM MQ BASE MP

• Fixed component ID

  5724H7251

Applicable component levels