Change deprecated Java example

[johantiden]

Fixes #1375

Changes

Change deprecated Java example Thread.currentThread().getId() to Thread.currentThread().threadId()

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• schema-next.yaml updated with changes to existing conventions.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: AlexanderWert / name: Alexander Wert (edd79e8)
• ✅ login: johantiden / name: Johan Tidén (1118a22)

[johantiden]

I read the CONTRIBUTING.md but it's unclear if I need to compile anything since I edited directly into an .md file.

[lmolkova]

thanks for updating it @johantiden!

I read the CONTRIBUTING.md but it's unclear if I need to compile anything since I edited directly into an .md file.

The markdown you changed is hand-written, so no need to re-generate anything