@ Override public AppEngineTransaction beginTransaction ( ) { if ( isTransactional ( ) ) { throw new IllegalStateException ( "Transaction has already started [" + transaction . get ( ) . id ( ) + "]" ) ; } AppEngineTransaction tx = new AppEngineTransaction ( this ) ; transaction . set ( tx ) ; logger . fine ( "Transaction [" + transaction . get ( ) . id ( ) + "] started" ) ; return tx ; }
Begins transaction . You have to do transactional operation after calling this method .