It may be database dependent. Here's extract from oracle docs http://download.oracle.com/docs/cd/B10501_01/java.920/a96654/oraperf.htm
After a batch exception, the update counts array can be retrieved using the getUpdateCounts() method of the BatchUpdateException object. This returns an int array of update counts, just as the executeBatch() method does. In the Oracle implementation of standard update batching, contents of the update counts array are as follows after a batch exception: - For a prepared statement batch, it is not possible to know which operation failed. The array has one element for each operation in the batch, and each element has a value of -3. According to the JDBC 2.0 specification, a value of -3 indicates that an operation did not complete successfully. In this case, it was presumably just one operation that actually failed, but because the JDBC driver does not know which operation that was, it labels all the batched operations as failures. You should always perform a ROLLBACK operation in this situation.
