Eclipse type hierarchy not always working

Question

When I want to see implementation of some interface through F4 (type hierarchy) or ctrl+t (quick hierarchy) or implementation of a method, I

Answer 1

I also had this problem and fixed it. The reason of this problem is that when the eclipse is running, I reinstall the JDK from 1.8 to 1.6. So I close eclipse, install JDK 1.8 again, then it's OK! May it will be helpful for others.

Answer 2

Use Eclipse clean mode for deleting caches, look here: How to run eclipse in clean mode? and what happens if we do so?

Sometimes is good to use clean mode to prevent these types of problems.

Answer 3

I had this same problem and fixed it by deleting the Eclipse index cache files located in .metadata/.plugins/org.eclipse.jdt.core. Delete all .index files and savedIndexNames.txt. Do this while Eclipse is not running and then restart. This fixed the issue for me.