configured System Vars vs install bundle(14 jdk + 6.7 netbeans)

I did not configured System Vars in 13 jdk update, well if I install bundle(14 jdk + 6.7 netbeans), System Vars will NOT needed RE-configured AGAIN (EITHER CONFIGURED BEFORE OR NOT?), CORRECT / NotCorrect

System Vars configuration is one time/identical, for all JAVA IDEs in the same PC? Are they required setup (like CLASSPATH, etc) to run java programs ? Please note I have no installed java IDE yet ...?

When update 15 of JDK comes out is needed/required any action from me ?
What about update 15 of JRE comes out ?

I plan develop JAVA/JSP: Desktop Apps, Web Apps, Mobile Apps, Web Mobile Apps...