java: static fields should be accessed in a static way

Change-Id: I727e7f2a7527c60bb45f0ba5d0e88a66c5ccdd6f
java: remove some unused fields

Change-Id: I1b6fb6b47439c448ac31983702772e2115c70d56
java: remove some unused local variables

Change-Id: Ia01528460e2f4b610d123e29cad66520abc6a965
java: remove some comment noise

Change-Id: I51118fecf9de27407b4c5a66cd6577574939e001