JTA(Java Transaction API)

JTA allows applications to perform distributed transactions—to access and update data on two or more networked computer resources. JTA support in a JDBC driver yields greatly increased data access power.
 understading JTA:    http://archive.devx.com/java/free/articles/dd_jta/jta-2.asp
 JTA software: http://java.sun.com/javaee/technologies/jta/index.jsp

The Java Transaction API (JTA) is one of the Java EE APIs allowing distributed transactions to be done across multiple XA resources. JTA is a specification developed under the Java Community Process as JSR 907. JTA provides for:

•             demarcation of transaction boundaries
•             X/Open XA API allowing resources to participate in transactionsurs

  The Java Transaction API consists of three elements: a high-level application transaction demarcation interface, a high-level transaction manager interface intended for an application server, and a standard Java mapping of the X/Open XA protocol intended for a transactional resource manager.
 
  UserTransaction interface

The javax.transaction.UserTransaction interface provides the application the ability to control transaction boundaries programmatically. This interface may be used by Java client programs or EJB beans.

The UserTransaction.begin method starts a global transaction and associates the transaction with the calling thread. The transaction-to-thread association is managed transparently by the Transaction Manager.

Support for nested transactions is not required. The UserTransaction.begin method throws the NotSupportedException when the calling thread is already associated with a transaction and the transaction manager implementation does not support nested transactions.

 Transaction context propagation between application programs is provided by the underlying transaction manager implementations on the client and server machines.