Replace simple uses of Iterator or index with a corresponding for-loop.
Use Arrays.fill(), String.join(), Collections.addAll(),
Collection.contains() and Collection.containsAll() instead of for loops.
Add useful breaks.
Remove useless continues.

Change-Id: I6cd913a02a644c0c5c2e7ec65adc2b918a86fe37
Signed-off-by: Carsten Hammer <carsten.hammer@t-online.de>