It has to do with how much memory is available for AS to create a VM environment for your app to populate. The thing is that ever since the update to 2.2 I've had the same problem every time I try to create a new project in AS.
How I solve it is by going into Project (on the left hand side) > Gradle Scripts > gradle.properties. When it opens the file go to the line under "(Line 10)# Specifies the JVM arguments used for the daemon process. (Line 11)# The setting is particularly useful for tweaking memory settings." You're looking for the line that starts with "org.gradle.jvmargs". This should be line 12. Change line 12 to this
org.gradle.jvmargs=-Xmx2048m -XX:MaxPermSize=512m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
After changing this line you can either sync the gradle with the project by clicking Try again on the notification telling you the gradle sync failed (it'll be at the top of the file you opened). Or you can simply close and restart the AS and it should sync.
Essentially what this is saying is for AS to allocate more memory to the app initialization. I know it's not a permanent fix but it should get you through actually starting your app.