NPE in Statement.getWarnings()

After executing a batch in a prepared statement, I call getWarnings() on that statement. A NPE is thrown.

at org.apache.derby.client.am.SqlWarning.getSQLWarning(SqlWarning.java:117)
at org.apache.derby.client.am.Statement.getWarnings(Statement.java:862)
...

Addtional info:

In a unit test, which worked for 10.8.2.2, a batch of 4 deletes were issued.
They were expected to fail, as there were no matching rows. There was a SQLWarning chain in the statement, 4 deep, one for each row that failed
with text:

No row was found for FETCH, UPDATE or DELETE; or the result of a query is an empty table.

However, each warning had 'nextException_' null. When attempting to chain on the exceptions when building the warning, a NPE is thrown.

Perhaps something like changing line 105 of SqlWarning.java to

if ( nextWarning_ != null && nextException_ != null )

Of course perhaps there's always supposed to be a corresponding exception.