Rebuild IntelliJ project indexes

Question

IntelliJ IDEA 10.5.1 is reporting zero usages for all method, classes etc.

Can I force IntelliJ to rebuild the project indexes?

Answer 1

File -> Invalidate caches...

(Force rebuild of all caches and indices on next startup)

Restart IntelliJ IDEA.

Caution: This might Remove local history.

Answer 2

Restarting IntelliJ fixed this in my case (Ultimate 2019.1) -- on restarting, it rebuild the indexes by itself.

An interesting side effect, apart from all imports and non-local references coming up as errors, was the error reported on all string literals:

Incompatible types. 
Required: java.lang.String 
Found: java.lang.String