Issue

• A threaddump shows that all request threads are blocked in an attempt to get a connection from the DB connection pool.

• A single thread in a synchronized block is creating a database connection

  ...
     java.lang.Thread.State: RUNNABLE
      at oracle.jdbc.driver.T2CConnection.t2cCreateState(Native Method)
      at oracle.jdbc.driver.T2CConnection.logon(T2CConnection.java:414)
      at oracle.jdbc.driver.PhysicalConnection. (PhysicalConnection.java:546)
      at oracle.jdbc.driver.T2CConnection. (T2CConnection.java:162)
      at oracle.jdbc.driver.T2CDriverExtension.getConnection(T2CDriverExtension.java:53)
      at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:521)
      at org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory.getLocalManagedConnection(LocalManagedConnectionFactory.java:207)
      at org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory.createManagedConnection(LocalManagedConnectionFactory.java:195)
      - locked <0x0000000782cd9730> (a org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory)
      at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.createConnectionEventListener(InternalManagedConnectionPool.java:650)
      at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.getConnection(InternalManagedConnectionPool.java:273)
      at org.jboss.resource.connectionmanager.JBossManagedConnectionPool$BasePool.getConnection(JBossManagedConnectionPool.java:689)
      at org.jboss.resource.connectionmanager.BaseConnectionManager2.getManagedConnection(BaseConnectionManager2.java:404)
      at org.jboss.resource.connectionmanager.TxConnectionManager.getManagedConnection(TxConnectionManager.java:424)
      at org.jboss.resource.connectionmanager.BaseConnectionManager2.allocateConnection(BaseConnectionManager2.java:496)
      at org.jboss.resource.connectionmanager.BaseConnectionManager2$ConnectionManagerProxy.allocateConnection(BaseConnectionManager2.java:941)
      at org.jboss.resource.adapter.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:96)
      ...
  

• Many other threads are blocked waiting for access to the connection

  ...
     java.lang.Thread.State: BLOCKED (on object monitor)
          at org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory.createManagedConnection(LocalManagedConnectionFactory.java:171)
          - waiting to lock <0x0000000782cd9730> (a org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory)
          at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.createConnectionEventListener(InternalManagedConnectionPool.java:650)
          at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.getConnection(InternalManagedConnectionPool.java:273)
          at org.jboss.resource.connectionmanager.JBossManagedConnectionPool$BasePool.getConnection(JBossManagedConnectionPool.java:689)
          at org.jboss.resource.connectionmanager.BaseConnectionManager2.getManagedConnection(BaseConnectionManager2.java:404)
          at org.jboss.resource.connectionmanager.TxConnectionManager.getManagedConnection(TxConnectionManager.java:424)
          at org.jboss.resource.connectionmanager.BaseConnectionManager2.allocateConnection(BaseConnectionManager2.java:496)
          at org.jboss.resource.connectionmanager.BaseConnectionManager2$ConnectionManagerProxy.allocateConnection(BaseConnectionManager2.java:941)
          at org.jboss.resource.adapter.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:96)
          ...