How to Identify connection leaks in JBoss for error "Unable to get managed connection for ...."

Issue

• Observing "Unable to get managed connection" and "No ManagedConnections available within configured blocking timeout" errors in theJBoss log

  Raw

  ... org.jboss.util.NestedSQLException: Unable to get managed connection for jdbc/TestDS; - nested throwable: (javax.resource.ResourceException: Unable to get managed connection for jdbc/TestDS)
       at org.jboss.resource.adapter.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:102)
       ...
  Caused by: javax.resource.ResourceException: Unable to get managed connection for jdbc/TestDS
       at org.jboss.resource.connectionmanager.BaseConnectionManager2.getManagedConnection(BaseConnectionManager2.java:441)
       at org.jboss.resource.connectionmanager.TxConnectionManager.getManagedConnection(TxConnectionManager.java:424)
       at org.jboss.resource.connectionmanager.BaseConnectionManager2.allocateConnection(BaseConnectionManager2.java:496)
       at org.jboss.resource.connectionmanager.BaseConnectionManager2$ConnectionManagerProxy.allocateConnection(BaseConnectionManager2.java:941)
       at org.jboss.resource.adapter.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:96)
       ...
  Caused by: javax.resource.ResourceException: No ManagedConnections available within configured blocking timeout ( 30000 [ms] )
       at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.getConnection(InternalManagedConnectionPool.java:311)
       at org.jboss.resource.connectionmanager.JBossManagedConnectionPool$BasePool.getConnection(JBossManagedConnectionPool.java:689)
       at org.jboss.resource.connectionmanager.BaseConnectionManager2.getManagedConnection(BaseConnectionManager2.java:404)
       ...
  

• How can connection leaks be identified?