java: remove some unused fields in the ODK examples

Change-Id: Ic6b4f18aefba6603af51d17d061e3f821e95261f
java: remove workarounds for missing functionality pre java 1.5

Since we now require java 1.5

Change-Id: I9e195f77c81bd9447f8e29c1862c68a57846c8a3
java: remove commented out code for OpenOffice 3.3

Specifically the comment says:
 This method not longer necessary since OOo 3.4 where the component registration
 was changed to passive component registration. For more details see
 http://wiki.openoffice.org/wiki/Passive_Component_Registration

Change-Id: Icfeec634ebc30a270533787b94e2a9a4318778db
java: implement optimisation in UnoRuntime#setCurrentContext

which is now available since we started requiring Java 1.5

Change-Id: I9847b89af7f487be7812a5717716900e9a517381