The Java Transaction API (JTA) is one of the Java Enterprise Edition (Java EE) API allowing distributed transactions to be done across multiple XA resources in a Java environment. 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 transactions.

JTA is the abbreviation for the Java Transaction API. JTS is the abbreviation for the Jave Transaction Service.

JTA provides a standard interface and allows you to demarcate transactions in a manner that is independent of the transaction manager implementation. The J2EE SDK implements the transaction manager with JTS. But your code doesn’t call the JTS methods directly. Instead, it invokes the JTA methods, which then call the lower-level JTS routines.

Therefore, JTA is a high level transaction interface that your application uses to control transaction. and JTS is a low level transaction interface and ejb uses behind the scenes (client code doesn’t directly interact with JTS. It is based on object transaction service(OTS)
which is part of CORBA.