I have the same the problem.
Here is my ionic info
Cordova CLI: 5.1.1
Ionic Version: 1.0.0
Ionic CLI Version: 1.5.0
Ionic App Lib Version: 0.1.0
ios-deploy version: Not installed
ios-sim version: 3.1.1
OS: Mac OS X Yosemite
Node Version: v0.12.4
Xcode version: Xcode 6.3.2 Build version 6D2105
I tried cordova build android
and it shows the same error:
Error: Could not find or load main class org.gradle.wrapper.GradleWrapperMain