Steps to reproduce:
1. On win7-x86, install the latest jre 8 nightly #463
2. Make sure you have one Admin user A and one Standard User S (or turn on the Guest account G)
3. Login as A, disable Java
4. Login as S or G, try to enable Java (when asked for Admin credential, do not type anything in passwd textbox, just click button "Yes"), if Java could be enabled, then the issue is reproduced.

Note: this issue could be reproduced no matter UAC is on or off.