Android Studio - Study

Eclipse + plug-in Android ADT -->  Eclipse ADT bundle -> Android Studio
Good materials (Chinese)
http://www.sdk.tw/2014/12/android-sdk-android-studio.html

Download Android Studio 1.4.1 is about 1.2 GB.

There is a known issue about Tools.jar is not in Android Studio classpath.
Just change your JAVA_HOME to JDK path. The tools.jar is not in JRE but in JDK.