java: don't catch and then just rethrow an exception

without doing anything else useful

Change-Id: I5803d84d46e0a70e1759f2202e2c2273087f8723
java: remove unnecessary constructor declarations

in the absence of any other constructors, the compiler will automatically
generate a public no-arg constructor

Change-Id: I70eca507cd8e16e33580b3398d41d70690bc2909
remove do-nothing code

Change-Id: I101cc3be44f029f7353e8d40823c0d6b2bd761b3
remove more unnecessary constructor declarations

Change-Id: Ie5a243006b112c2e6daf12992f3dba8baf12748d