Like Vito mentions, this error occurs after Java updates as the path:
C:\ProgramData\Oracle\Java\javapath
is added to the Path environment variable, causing Eclipse to run using the wrong java version.
To fix the problem:
1) Right-click on Computer and choose Properties.
2) Click Advanced system settings
3) Click Environment Variables...
4) Find the Path variable in the System variables section.
5) Choose it and click Edit...
6) Find and delete the above mentioned path.
This fixed it for me. I should mention that I already have the path:
c:\Program Files\Java\jdk1.7.0_21\bin
in the Path variable, but the new path was added to the beginning of the Path variable and therefore resolution would use that path first.