I have recently found out the hard way that Oracle has decided to silently nuke JRE 6 when a JRE7 update is installed.
Is it possible to leave JRE7 on auto-update without breaking JRE6? If not, how else can we ensure JRE6 stays? Is there a better way than manually reinstalling it after every single JRE7 update?
(the legacy apps will hopefully be updated to JRE7 sooner or later, but we didn't write them, so we can't update them)
Best Answer
Does your JRE6 need to be "installed" through Programs and Features? If not, you can simply copy the JRE files to a predefined location on your disk (your apps will have to point to this), then JRE 7 would be unaware of the presence of JRE 6 and would not delete it.
Otherwise, another option would be to make your JRE 6 folder "read only" so that the JRE7 installer can't nuke it.
Also, it is only recently that the JRE7 installer nuked the JRE6 install (I think starting with 7 update 13). This is because of the recent Java "zero day exploits" that have compromised previous versions of Java. However, if you have an older version of JRE6 installed, the JRE7 installer may not nuke those older JRE6 installs.