Keyboard shortcuts and various tips for IntelliJ IDEA. This document assumes IntelliJ on a Mac, using the Keymap setting for Mac OS X 10.5+ (in Preferences > Keymap). I know you can get all these through Help > Keymap Reference in IntelliJ, but I like to maintain my own list so that I can organize and search it the way I prefer, plus have a place to add my own additional notes.
Comment / uncomment selected text
Select block of text and then press Command + /
Spread selection from cursor (to word, then line, etc.)
ALT + up arrow or down arrow
Format selected code
CTRL + ALT + I
Format all code
ALT + CMD + L
Autocomplete method parameter info
CMD + P (when cursor is in method signature)
Invoke a Surround Template (ex: surround a line with try/catch)
OPTION + CMD + T
Complete a statement
SHIFT + CMD + ENTER
Tool Windows and Dialogs
CMD + 1
CMD + 9
CMD + ,
SHIFT + COMMAND + F8
CMD + E
SHIFT + SHIFT
CMD + O
OPTION + CMD + O
Navigate back and forth through recent files
CMD + [ and CMD + ]
New file (where selection is in Project window)
CMD + N
Note: you can use slashes to create entire trees abc/def/ghi/jkl...
Hide all other windows
SHIFT + CMD + F12
Stretch pane right or left
SHIFT + CMD + left or right arrow
SHIFT + CMD + V
Method List (of the active editor file)
CMD + F12
CMD + up arrow
Note: This is particularly useful if you turn off the normal navigation bar in preferences to save UI space.
SHIFT + CMD + A (try, for example, "RESTful Web Service")
Version Control Quick List
CTRL + V
Quick Switch Settings
CTRL + ~
CTRL + J (and then again to pin it open at larger size).
Live templates can be found in Preferences > Editor > Live Templates. Learn them!
To use a live template, enter its short text in the editor and then press tab to replace the short text with its template.