The results of these experiments puzzle me. I think it is odd that you need credentials to bring down the engine, but you don't need credentials to bring down the network server--which then brings down the engine as a side effect. Is this behavior expected and correct right now?
Possibly you are seeing DERBY-51. That is, I don't think that bringing down the network server actually does bring down the engine. It just crashes the JVM, leaving the engine to recover the next time you connect to that database.
http://issues.apache.org/jira/browse/DERBY-51 thanks, bryan
