Cleanup documentation and modifiers

[holgerfriedrich]

• Cleanup Javadoc annotations (removing brackets from {@return statements})
• Change modifiers according to JLS (mainly removing final from static methods, as static methods are implicitly final, but also order of modifiers)
• Minor other improvements

[holgerfriedrich]

Hi @bmalinowsky, sorry for replying late.

I followed your advice and rolled back accordingly. Seems this PR is down to two minor changes....

[bmalinowsky]

Thanks for the PRs!