Resource Handling Mechanism 

Application components that access a database need transactions to ensure the integrity of the data stored in the database. Furthermore, certain resources, such as connections, are used to enable the execution of the distributed transactions. The process of assigning a resource to a distributed transaction is called enlisting. The process of releasing resources is called delisting.

The resource handling functions in the J2EE Engine are provided by the Transaction Service and the Connector Container Service. You can connect to back-end systems using J2EE Connector Architecture resource adapters. The Connector Container Service is a container for these adapters and provides their access to system-level resources. It is responsible for the centralized management of the connections provided by the deployed adapters in terms of transactions, security and connection pooling. In these activities it interacts with the Transaction Service as well.

The behaviour of the connections that you obtain and use in your applications depends on the following factors:

·        If the connection is used in a transaction

·        If it is a shared resource

The J2EE Engine also provides the JDBC Connector Service that implements the logic of a resource adapter for connections to a relational database. You can use this service to register DataSources, which act as factories for database connections. For more information about, see Database Connection Management.