Useful intelliJ shortcuts those are good know.

How to remove unused imports in intelliJ?

In Mac IntelliJ IDEA, the command is:

Cmd + Option + o

(Letter o not Zero 0)

For some older versions it is apparently Ctrl + Option + O.

Ctrl + Option + o

(Letter o not Zero 0)

For windows, the command is:

Ctrl + Alt + o

(Letter o not Zero 0)

How to open recently closed files?

In Mac IntelliJ IDEA, the command is:

Cmd + e

For windows, the command is:

Ctrl + e