Setup IntelliJ IDE

Change IntelliJ IDE Theme

1. Copy the BlueForest.xml file into the /colors directory underneath your IDEA installation folder
/Users/xxx/Library/Preferences/IntelliJIdea12/colors/

2. IntelliJ IDEA -> Preference -> Editor -> Colors&Fonts -> Scheme Name -> Darcula.

3. Restart IntelliJ, then Choose Scheme Name: BlueForest.

Change Code Front Size

In Mac OS
1. The leftmost tab "IntelliJ IDEA" -> Preferences -> Editor -> General -> Check "Change front size" -> OK
Then "Command" + mouse wheel

In Windows/Linux, "File"-> Settings


See Welcome Screen everything restart the IDE

"File" -> "Settings" -> "Appearance & Behavior" -> "System Settings"
uncheck "Reopen last project on startup"

Set Default Indentation

File > Settings... > Editor > Code Style > Java > Tabs and Indents > 

To toggle between tabs and spaces
On the main menu, choose Edit | Convert Indents , and then choose To Spaces or To Tabs respectively.

Reference:
https://github.com/sirthias/BlueForest