I understand that JCA simplifies the way in which App servers access diffrent RDBMS or EIS system. As an Application developer how does JCA help me,should i use it or getting connction using Datasources and JDBC drivers enough.
I'm certainly no expert, but the way I think about JCA is an abstraction layer above JDBC. For example, I may have an adapter that uses JDBC to access a database, or one that accesses a message queue.
Basically, if you're developing large scale enterprise applications that integrate legacy or disparate systems, you may want to look at the JCA spec. Or, if you're working with JBoss or another web server that uses JCA in it's architecture, then you may want to look at it. On the other hand, if you're building applications that simply read and write data to a relational database, JDBC will serve your purposes.