JRE for browsers (mine was 1.8.0_101, 160mb, was up to date):
/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java
JDK, JRE installed with installer:
/Library/Java/JavaVirtualMachines/
I had only:
$ du -d1 -h
312M ./jdk1.8.0_25.jdk
Was not up to date.
After installing U101, I had:
$ du -d1 -h
338M ./jdk1.8.0_101.jdk
312M ./jdk1.8.0_25.jdk
I removed the old one.