[Doc] Java API: add information on JBoss EAP

Closes #3445.
Bootstrap.java: fix PID file creation

This change fixes various failure modes on PID file creation which have been
introduced by using nio:
- check if PID file has a directory part
- Allow PID directory creation fail w/ FileAlreadyExistsException
  (thrown if directory exists and is a soft link)
- create PID file if it doesn't exist, truncate it if it does

fixes #8771

Signed-off-by: Thilo Fromm <github@thilo-fromm.de>
Merge branch 'fix/8771-pid-file-creation-fails' into fix/8493-systemd-service-file-for-debian