The jtm service is used by ejb2 service in order to provide transaction management for EJB components as defined in the deployment descriptor. The jtm service uses a Transaction manager that may be local or may be launched in another JVM (a remote Transaction manager). Typically, when there are several JOnAS servers working together, one jtm service must be considered as the master and the others as slaves. The slaves must be configured as if they were working with a remote Transaction manager.

By default JOTM is the Transaction manager used.

Here is the part of jonas.properties concerning the jtm service:

###################### JOnAS JTM Transaction service configuration
#
#  Set the name of the implementation class of the jtm service
jonas.service.jtm.class    org.ow2.jonas.tm.jotm.JOTMTransactionService

#  Set the Transaction Manager launching mode.
#  If set to 'true', TM is remote: TM must be already launched in an other JVM.
#  If set to 'false', TM is local: TM is going to run into the same JVM
#  than the jonas Server.
jonas.service.jtm.remote    false

#  Set the default transaction timeout, in seconds.
jonas.service.jtm.timeout    60

For customizing the jtm service It is possible to