To update mozilla/firefox etc

copy c:\java142\bin\npj2*.* to your browser plugins directory.
you will also require the ipluginw.dll

Java Web Start
Open the helper application settings
Define a new entry as follows :-

Description of type: Java Web Start
File Extension: jnl jnlp
MIME type: application/x-java-jnlp-file
Application to use: C:\java142\javaws\javaws.exe

Set your user home directory in config.sys

SET USER_HOME=D:\APPS  (or whatever)