Overhaul Java client section

[akeller]

All docs should be SaaS-first (if significantly different from Self-Managed, we should explore creating a dedicated instruction section for APIs & Tools in Self-Managed).

The structure of the Java client section should look as follows:

• Quick reference, including links to client docs and client source code repo
• Getting started (sample project, runnable code)
• Example should include code snippets and expected/sample results for the following:
  • Process
  • Deploy process
  • Create a process instance
  • Decision evaluation
  • Creating a job worker
  • Sending a message (message correlation)
  • Working with data/variables
  • Error handling
  • Backpressure
  • Slow/unavailable engine
• Testing

Ensure logging works for SaaS-based use cases.

I recommend reaching out to consulting for a review of new code snippets and any additional examples we should include.

[akeller]

@jwulf this might be a quick win if you want to take the code you wrote in training, modify it a bit, and use it in the docs. I know the existing code is available in a community project, but I don't see a hard requirement for new code snippets to live there.

[akeller]

Can rework example from Best Practices:

zeebeClient.newPublishMessageCommand() //
  .messageName("messageA")
  .messageId(uniqueMessageIdForDeduplication)
  .correlationKey(message.getCorrelationid())
  .variables(singletonMap("paymentInfo", "YeahWeCouldAddSomething"))
  .send()
  .exceptionally( throwable -> { throw new RuntimeException("Could not publish message " + message, throwable); });

There might be others on the page as well - https://docs.camunda.io/docs/components/best-practices/development/connecting-the-workflow-engine-with-your-world/#calling-zeebe.

[akeller]

PIM example requested - https://camunda.slack.com/archives/C026U8GBNSW/p1704243018583379

Could look at turning https://www.loom.com/share/a2e680afc1ed49838e92a6c50f18ee23 into docs.