Google OAuth Client Library for Java Written by Google, this library is a powerful and easy to use Java client library for the OAuth 2 and OAuth 1.0a standards for authorization. It is built on the Google HTTP Client Library for Java. Supports these Java environments: Java 5 (or higher) standard (SE) and enterprise (EE) Android 2.1 (or higher) Google App Engine For access to Google APIs, please take a look at the Google API Client Library for Java.