question: public static boolean rollback ( boolean throwException , String trxName ) throws SQLException { try { Connection conn = null ; Trx trx = trxName == null ? null : Trx . get ( trxName , true ) ; if ( trx != null ) return trx . rollback ( true ) ; else conn = DB . getConnectionRW ( ) ; if ( conn != null && ! conn . getAutoCommit ( ) ) conn . rollback ( ) ; } catch ( SQLException e ) { log . log ( Level . SEVERE , "[" + trxName + "]" , e ) ; if ( throwException ) throw e ; return false ; } return true ; }
target:  Rollback - rollback on RW connection. Is has no effect as RW connection is AutoCommit (exception: with transaction)