ChangeNumberIndexer.java:
In run(), made sure all cursors are properly closed, even in case of a RuntimeException terminating the thread.
Moved resetNextChangeForInsertDBCursor() out of removeAllCursors().
In removeAllCursors(), closed the CompositeDBCursor.

ServerHandler.java:
Made shutdownWriter volatile.

JEReplicaDBCursor.java:
Avoided a NullPointerException.