If one of the commands in a batch update fails to execute properly, this method throws a BatchUpdateException, and a
JDBC driver may or may not continue to process the remaining commands in the batch. However, the driver's behavior must be consistent with a particular DBMS, either always continuing to process commands or never continuing to process commands. If the driver continues processing after a failure, the array returned by the method BatchUpdateException.getUpdateCounts will contain as many elements as there are commands in the batch, and at least one of the elements will be the following:
A value of EXECUTE_FAILED -- indicates that the command failed to execute successfully and occurs only if a driver continues to process commands after a command fails
Please refer here for more details:
http://java.sun.com/javase/6/docs/api/java/sql/Statement.html#executeBatch%28%29