Oh yes, I’m back learning java from the beginning. I’m using eclipse mars as my IDE. There were times I just shutdown my windows box without closing my eclipse properly. That may have cause the issue whereby I cannot open anymore the workspace of mine and the practice projects / files I created in java. I managed to fix the issue somehow and recovered my workspace projects that are still existing in my hard drive .
step 1) delete the workbench.xmi in this directory
C:\Users\yourusername\workspace\.metadata\.plugins\org.eclipse.e4.workbench
step 2) restart eclipse
step 3) once restarted and chosen your workspace that got corrupted, click file -> import -> existing projects into workspace -> browse -> select the directory of the project and click ok. that’s it 😀