AVRO-3889: [Java][Build] Maven IDL Generation Modification Check

[briancullen]

What is the purpose of the change

This change adds an up to date check to the maven plugin when generating Java classes from avro IDL. The reason for the change is to prevent unnecessary recompilation of the java source code in projects using the plugin.

Verifying this change

This change added tests and can be verified as follows:

• Added tests to verify that only missing files are regenerated when processing the avro IDL files.
• Altered existing tests to ensure that files are generated and not used from previous test runs.

Not sure if there are other scenarios that may be affected by this change.

Documentation

This pull request does not introduce a new feature and is not documented.

[briancullen]

@opwvhk forgive the question but I’m not sure what the process for this project is. Is it ok for me to merge now and should I make the equivalent PR for master?

[martin-g]

@briancullen Can you see the Squash and merge button ?

[briancullen]

@martin-g actually no, now that you mention it, I can't see a merge button. Presumably as I don't have write access to the repository. I should have probably looked before I asked, sorry.

[martin-g]

No worries! The PR will be merged soon! Definitely before the next release!

[briancullen]

@martin-g thanks for the feedback. Not sure if you wanted it but I created a similar pull request for the main branch and linked it to this (see #2564). Feel free to merge if you feel it is useful.

[briancullen]

@martin-g Just to follow up on this. Can this pull request, and possibly #2564, be merged? Also, out of curiosity, is there any timeline for when there might be another release?

[martin-g]

Hi @briancullen !

I maintain the Rust SDK.
But I see that @opwvhk (a Java developer!) already approved this PR, so I can merge it for you!

About the release: you can follow this discussion at dev@avro.apache.org - https://lists.apache.org/thread/sfmpn6dmrfpv4169tqx4klbw2dyqmz3z