11.7.3. Begin a Transaction

Get an instance of UserTransaction.

• JNDI

  new InitialContext().lookup("java:comp/UserTransaction")

• Injection

  @Resource UserTransaction userTransaction;

• Context

  • In a stateless/stateful bean:

    @Resource SessionContext ctx;
    ctx.getUserTransaction();

  • In a message-driven bean:

    @Resource MessageDrivenContext ctx;
    ctx.getUserTransaction()

Call UserTransaction.begin() after you connect to your datasource.

...
try {
    System.out.println("\nCreating connection to database: "+url);
    stmt = conn.createStatement();  // non-tx statement
    try {
        System.out.println("Starting top-level transaction.");
        userTransaction.begin();
        stmtx = conn.createStatement(); // will be a tx-statement
        ...
    }
}