Let's now review in what scenarios the connection transaction mode changes from one mode to another mode in an Oracle database.

Key Oracle components that take part in XA transactions are as follows:

• OracleXADataSource: This acts as the data source for the XA transaction; it is the producer of the XA connections. It implements the XADataSource interface. Additionally, it extends the OracleConnectionPoolDataSource class that extends the OracleDataSource class.
• OracleXAConnection: This acts as an instance of the pooled connection for the database. It implements the XAConnection interface that extends the PooledConnection interface. Additionally, it extends the OraclePooledConnection class.
• OracleXAResource: This is the handle for the transaction manager to organize each transaction. It implements the XAResource interface. OracleXAResource is available in both the client and server packages to act as both types of resource.
• OracleXid: This acts as transaction identifiers for the transaction manager to organize the transactions. It implements the Xid interface.
• OracleXAException: This is the exception thrown by XA methods if an exception occurs during the transactions. It is a subclass of the XAException.