Ctrl + Space Basic code completion (the name of any class, method or variable)
Ctrl + Shift + Space Smart code completion (filters the list of methods and variables by expected type)
Ctrl + Shift + Enter Complete statement
Ctrl + P Parameter info (within method call arguments)
Ctrl + Alt + L Reformat code***
Ctrl + Alt + O Optimize imports
Ctrl + F4 Close active editor tab
Ctrl + Shift + F Find in path
Ctrl + Shift + R Replace in path
Ctrl + Shift + S Search structurally (Ultimate Edition only)
Ctrl + Shift + F7 Highlight usages in file
Ctrl + Alt + F7 Show usages
F9 Resume program
Ctrl + N Go to class
F12 Go back to previous tool window
Esc Go to editor (from tool window)
Ctrl + E Recent files popup
Ctrl + Alt + Left/Right Navigate back/forward
Shift + F6 Rename
Ctrl + F6 Change Signature
Ctrl + K Commit project to VCS
Ctrl + T Update project from VCS
Alt + Shift + C View recent changes
Ctrl + Alt + Y Synchronize
Ctrl + Shift + F12 Toggle maximizing editor
Alt + Shift + F Add to Favorites
Ctrl + Alt + S Open Settings dialog
Ctrl + Alt + Shift + S Open Project Structure dialog