General SQL Parser (GSP) is a quite feature rich SQL parser (to the extent that I have played with it) that allows for modifying SQL statements in a robust way by altering the parse tree itself. Furthermore, it supports SQL flavors for most popular databases. However, a big minus with GSP is that it is horribly, simply horribly, documented: the javadoc's consist mostly of the raw method and property names (with almost no comments), there are really no documentation that outlines the core functionality and the meaning of most important properties and methods; and it seems like they have just exposed everything as public members, making the API very hard to grasp by looking at it. The only documentation is a bunch of practical examples from which you have to reverse-engineer the meaning of the API calls yourself.
I do not like producing production critical software with a library like that. So due to the above, I would prefer using another parser, but have unfortunately failed to find any alternatives (for java) with similar functionality and support for multiple SQL flavors.
Are there any comparable (!) alternatives to GSP for java out there?