NullPointerException in AbstractJdbc2DatabaseMetaData.getUDTs

I am encountering an intermittent NullPointerException when I call connection.getMetaData().getUDTs(). I traced it to a null key in TypeInfoCache._pgNameToSQLType, inserted by a previous call to connection.getMetaData().getTypeInfo(), as a result of a lingering temporary table.

I attached a basic reproducer. For me it usually fails on the second or third time through the loop.

I am using the latest driver (9.3-1101-jdbc41), and I get the same results running against 9.2 and 9.3 servers.

- Elizabeth Chatman