IntelliJ IDEA

Open any resource
Press SHIFT twice
 Shortcut Keys
http://www.shortcutworld.com/en/win/IntelliJ.html


Jump to matching brace {}
place cursor anywhere inside the block
Press Ctrl { or Ctrl } to goto open / close brace

Goto any menu
Ctrl + Shift A + enter menu (action name)

Alt   1 - view project structure
Alt   7 - view class outline
Alt  F7 - view usages of a function
Ctrl  H - view class hierarchy

(press same key again to hide/toggle)

Execute Any maven goal
View -- Tool Windows -- Maven Project
Click on M(aven) icon 
Execute Maven goal command box will be displayed
(alternatively Press Ctrl + Shift + A - enter 'Execute Maven Goal')

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View /Hide - Run window
Alt + 4


Add external jar files to project
File --> Settings(Ctrl +  Alt + Shift + S)

'Project Structure' window opens.
Under 'Project Settings' -> Modules 
Click '+' button to add jar files.


Commenting lines / blocks of code
Select the blocks of lines to comment
Ctrl + /    line comment
Ctrl + Shift + /   block comment