Weird NPE on BatchingBatcher "JDBC driver did not return the expected number of row counts"

Question

I'm running a spring/hibernate java app on tomcat and I'm seeing this funky error on update: JDBC driver did not return the expected number of row counts

Caused by: java.lang.NullPointerException
        at org.hibernate.jdbc.BatchingBatcher.checkRowCounts(BatchingBatcher.java:90)
        at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:70)
        at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:268)
        at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:262)
        at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:179)

I recently updated my mysql connector to version 5.1.15. Has anyone seen anything like this?

Answer 1

I think I encountered this once and fixed it by implementing hashCode and Equals methods for the object type returned by the query.