How to put Maven-generated sources under version control?

Question

I'm using Maven to build and deploy jOOQ. I now want to start generating XJC-generated classes using appropriate Maven plugins (before, I used ant scripts). This works very nicely for me, but I'm afraid that some users wanting to build jOOQ themselves without Maven will now have trouble generating those missing sources. So I'd like to move those sources out of target/generated-sources/xjc and into src/main/java, in order to be able to put them under version control.

• Is this a common practice?
• How can I do it (should I use plugins to move the files on a low-level, or should I generate files directly into src/main/java)?
• Do I have other options?

Note, the underlying XSD hardly ever changes, so I don't have to generate these sources every time I build...

Answer 1

This is a terrible idea, you should never put generated sources in version control because whatever they are being generated from can change, and then your code is out of sync.

Even if the XSD never changes, note I said never, not hardly ever, as you said, which is different, I would not put the sources under version control. Maven can be told to not generate the sources every time if the XSD hasn't changed.

If you go down the Maven route, then anyone building your stuff should use the same tool chain. This is not specific to Maven. If this was Ant, or a C++ project with a make file, you wouldn't want to do this either.

If you really want to provide a Maven free stand alone distribution, then have Maven generate that, there are plenty of plugins that will export all the artifacts as an archive that you can distribute. But don't compromise your build for some nebulous external requirement that may not exist.

Answer 2

Maybe an alternative is to use the Maven assembly plugin to zip all those sources and expose those as a versioned artifact. The dependency plugin would allow you to pull in those sources from a local or remote repository and make sure you have the correct version of those sources.

(In my opinion, leave it like it is. If Maven is your build system, everybody trying to build your code should use that)