I had to manually specify the JDK in Eclipse. Go to Window -> Preferences -> Java -> Installed JREs. In my case the only line in the list was for the JRE. Click on "Add..." -> Standard VM and put in the JRE Home directory where the Java JDK resides. On my systems it is "C:\Program Files (x86)\Java\jdk1.8.0_31". Make sure the new JDK line is checked, not the JRE line.
Eclipse is a mess.
Bob