The Full Form of JCA is‍ Java EE Connector Architecture.

Jakarta Connectors is a Java-based tool for connecting application servers and enterprise information systems as part of enterprise application integration solutions. While JDBC is specifically used to connect Java applications to databases, JCA is a more generic architecture for connection to legacy systems. 

The Connector architecture enables Java EE components to interact with enterprise information systems (EISs) and EISs to interact with Java EE components. EIS software includes various types of systems: enterprise resource planning (ERP), mainframe transaction processing, and nonrelational databases, among others. Connector architecture simplifies the integration of diverse EISs. Each EIS requires only one implementation of the Connector architecture. Because an implementation adheres to the Connector specification, it is portable across all compliant Java EE servers.

The Java EE Connector Architecture enables Java EE components to interact with enterprise information systems (EISs) and EISs to interact with Java EE components. EIS software includes such kinds of systems as enterprise resource planning (ERP), mainframe transaction processing, and nonrelational databases. Connector architecture simplifies the integration of diverse EISs. Each EIS requires only one implementation of the Connector architecture. Because it adheres to the Connector specification, an implementation is portable across all compliant Java EE servers.

The specification defines the contracts for an application server as well as for resource adapters, which are system-level software drivers for specific EIS resources. These standard contracts provide pluggability between application servers and EISs. The Java EE Connector Architecture 1.6 specification defines new system contracts such as Generic Work Context and Security Inflow. The Java EE Connector Architecture 1.6 specification is available at http://jcp.org/en/jsr/detail?id=322.

A resource adapter is a Java EE component that implements the Connector architecture for a specific EIS. A resource adapter can choose to support the following levels of transactions:

• NoTransaction: No transaction support is provided.

• LocalTransaction: Resource manager local transactions are supported.

• XATransaction: The resource adapter supports the XA distributed transaction processing model and the JTA XATransaction interface.