I am trying to get my first taste of Android development using Eclipse. I ran into this problem when trying to run Eclipse, having installed version 4.2 only minutes ago.
For me the solution was to go into (on Windows 8.1):
System > Advanced system setting > Environment Variables
Under 'System variables' in the 'Path' variable there was the following first:
C:\ProgramData\Oracle\Java\javapath;
I removed this and Eclipse worked again!