// 1st attempt.
UserTransaction.begin();
Connection conn = dataSource.getConnection();
Statemnt stmt = conn.createStatement();
stmt.executeUpdate("...");
UserTransaction.commit(); // XAResource#commit() failure with ARJUNA016039.

// retry transaction.
UserTransaction.begin();
Connection conn = dataSource.getConnection(); // returned same physical connection of the previous transaction.
Statemnt stmt = conn.createStatement();       // SQLException thrown by the connection is already closed.

// 1st attempt
WARN  [com.arjuna.ats.jta] (default task-1) ARJUNA016039: onePhaseCommit on < formatId=131077, gtrid_length=29, bqual_length=36, tx_uid=0:ffff7f000001:21fea082:5dc8ed99:f, node_name=1, branch_uid=0:ffff7f000001:21fea082:5dc8ed99:14, subordinatenodename=null, eis_name=java:jboss/datasources/ExampleDS > (LocalXAResourceImpl@6cb4daa9[connectionListener=6a0eecdd connectionManager=36f87501 warned=false currentXid=null productName=H2 productVersion=@PROJECT_VERSION@ (2016-10-31) jndiName=java:jboss/datasources/ExampleDS]) failed with exception XAException.XA_RBROLLBACK: org.jboss.jca.core.spi.transaction.local.LocalXAException: IJ001156: Could not commit local transaction
	at org.jboss.jca.core.tx.jbossts.LocalXAResourceImpl.commit(LocalXAResourceImpl.java:182)
	at com.arjuna.ats.internal.jta.resources.arjunacore.XAOnePhaseResource.commit(XAOnePhaseResource.java:120)
	at com.arjuna.ats.internal.arjuna.abstractrecords.LastResourceRecord.topLevelOnePhaseCommit(LastResourceRecord.java:172)
	at com.arjuna.ats.arjuna.coordinator.BasicAction.onePhaseCommit(BasicAction.java:2386)
	at com.arjuna.ats.arjuna.coordinator.BasicAction.End(BasicAction.java:1497)
	at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.end(TwoPhaseCoordinator.java:96)
	at com.arjuna.ats.arjuna.AtomicAction.commit(AtomicAction.java:162)
	at com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionImple.commitAndDisassociate(TransactionImple.java:1287)
	at com.arjuna.ats.internal.jta.transaction.arjunacore.BaseTransaction.commit(BaseTransaction.java:126)
	at com.arjuna.ats.jbossatx.BaseTransactionManagerDelegate.commit(BaseTransactionManagerDelegate.java:94)
	at org.wildfly.transaction.client.LocalTransaction.commitAndDissociate(LocalTransaction.java:75)
	at org.wildfly.transaction.client.ContextTransactionManager.commit(ContextTransactionManager.java:71)
	at org.wildfly.transaction.client.LocalUserTransaction.commit(LocalUserTransaction.java:53)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.jboss.weld.util.reflection.Reflections.invokeAndUnwrap(Reflections.java:410)
	at org.jboss.weld.bean.builtin.CallableMethodHandler.invoke(CallableMethodHandler.java:42)
	at org.jboss.weld.bean.proxy.EnterpriseTargetBeanInstance.invoke(EnterpriseTargetBeanInstance.java:56)
	at org.jboss.weld.bean.proxy.ProxyMethodHandler.invoke(ProxyMethodHandler.java:106)
	at org.jboss.weldx.transaction.UserTransaction$$Proxy$_$$_Weld$Proxy$.commit(Unknown Source)
	at com.example.HelloServlet.doGet(HelloServlet.java:65)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:686)
    ...

// 2nd attempt 
ERROR [stderr] (default task-1) org.h2.jdbc.JdbcSQLException: The object is already closed [90007-193]
ERROR [stderr] (default task-1) 	at org.h2.message.DbException.getJdbcSQLException(DbException.java:345)
ERROR [stderr] (default task-1) 	at org.h2.message.DbException.get(DbException.java:179)
ERROR [stderr] (default task-1) 	at org.h2.message.DbException.get(DbException.java:155)
ERROR [stderr] (default task-1) 	at org.h2.message.DbException.get(DbException.java:144)
ERROR [stderr] (default task-1) 	at org.h2.jdbc.JdbcConnection.checkClosed(JdbcConnection.java:1480)
ERROR [stderr] (default task-1) 	at org.h2.jdbc.JdbcConnection.checkClosed(JdbcConnection.java:1458)
ERROR [stderr] (default task-1) 	at org.h2.jdbc.JdbcConnection.createStatement(JdbcConnection.java:202)
ERROR [stderr] (default task-1) 	at org.jboss.jca.adapters.jdbc.WrappedConnection$1.produce(WrappedConnection.java:357)
ERROR [stderr] (default task-1) 	at org.jboss.jca.adapters.jdbc.WrappedConnection$1.produce(WrappedConnection.java:355)
ERROR [stderr] (default task-1) 	at org.jboss.jca.adapters.jdbc.SecurityActions.executeInTccl(SecurityActions.java:97)
ERROR [stderr] (default task-1) 	at org.jboss.jca.adapters.jdbc.WrappedConnection.createStatement(WrappedConnection.java:355)
ERROR [stderr] (default task-1) 	at com.example.HelloServlet.doGet(HelloServlet.java:59)
...

    "If the resource manager did not commit the transaction and the paramether onePhase is set to true, the resource manager may throw one of the XA_RB* exceptions. 
    Upon return, the resource manager has rolled back the branch's work and has released all held resources."
    https://docs.oracle.com/javase/8/docs/api/javax/transaction/xa/XAResource.html#commit-javax.transaction.xa.Xid-boolean-

// 1st attempt.
UserTransaction.begin();
Connection conn = dataSource.getConnection();
Statemnt stmt = conn.createStatement();
stmt.executeUpdate("...");
conn.close(); // connection close is called before commit.
UserTransaction.commit(); // XAResource#commit() failure with ARJUNA016039.

// retry transaction.
UserTransaction.begin();
Connection conn = dataSource.getConnection(); // valid connection will be returned.