Android Studio is giving me a Gradle build error that looks like this:
Error:(3, 22) compileSdkVersion android-22 requires compiling with JDK 7
You can use cmd + ; for Mac or Ctrl + Alt + Shift + S for Windows/Linux to pull up the Project Structure dialog. In there, you can set the JDK location as well as the Android SDK location.

To get your JDK location, run /usr/libexec/java_home -v 1.7 in terminal. Send 1.7 for Java 7 or 1.8 for Java 8.