docs/lang/java: Cleanup/clarify.
docs/lang/java: Cleanup/clarify.

Capitalization, punctuation, and a bit more detailed in some places,
catering for people who may be not too familiar with Java.

windelbouwman/ppci-mirror,windelbouwman/ppci-mirror,windelbouwman/ppci-mirror,windelbouwman/ppci-mirror,windelbouwman/ppci-mirror,windelbouwman/ppci-mirror