I started some work on my branch, and it's not looking good. It's probably not entirely our fault though, seems the JSR-352 APIs seem to be quite buggy in Spring Batch. Which I guess is to be expected: it's not their primary API, so it's probably not as thoroughly tested as their native API.

• I had to work around Spring Batch not supporting references to the partition plan in <chunk item=...>
• the job is affected by a blocking bug: BATCH-2441
• there is some other bug I coulnd't identify that prevents us from accessing the job context's transient data from chunk listeners (StepProgressSetupListener in our case)
• CheckpointAlgorithms in Spring batch seem completely broken (or require some configuration that I didn't understand):
• Spring Batch will not trigger a checkpoint implicitly when the EntityReader returns null, it will always wait for the CheckpointAlgorithm#isReadyToCheckpoint to return true. And we don't have any information about what EntityReader returned within the checkpoint algorithm... The problem is probably in CheckpointAlgorithmAdapter#isComplete, it should set isComplete to true if result is RepeatStatus.FINISHED.
• When CheckpointAlgorithm#isReadyToCheckpoint finally returns true, it seems to stop the batch completely without even performing the write!

And I'm sure the list goes on and on... I will stop there for now, because I will probably need to checkout the Spring Batch project and have a look at the JSR-352 tests... and add a few. Which will probably take a lot of time.