bwalenz: I tried using MapBackedDictionary with JWNL 1.4-RC2 and I wasn't able to get it to work without making some modifications.
When I run my program, what it does is look for a table called "exception", which is nonexistent. Instead, there's a generated table called "synsetexception" that I renamed.
Second, it looks for a field called "exception" in that table, and again there isn't one. There is one called "s_exception" that I had to rename to get it to work.
Sorry for the confusion, I meant DatabaseBackedDictionary, not MapBackedDictionary.
Also the function Synset.getLexFileName() always returns null because the lexfile data is nonexistent in the tables.
I fixed this in my fork at http://extjwnl.sourceforge.net/