Eclipse unable to generates classes while using AWS SWF

I am following hello world application of Amazon Web Services Simple Workflow Service. According to description @Activities annotation should have been able to generate two classes GreeterActivitiesClient and GreeterActivitiesClientImpl. But these classes has not been generated.

I have Enable annotation processing in project properties. I am using Eclipse Mars with Jdk 1.8. I have also installed AWS toolkit for eclipse, aspectj.

Can someone see where the problem is?

Solution

Some versions of Eclipse, (notably Mars and Neon), may fail to fetch the latest artifacts due to a bug in old versions of the Oomph plugin. To work around this issue:

Make sure that you’re using https://aws.amazon.com/eclipse/site.xml as the AWS Toolkit for Eclipse update site.
Delete the ~/.eclipse/org.eclipse.oomph.p2/cache/ directory to remove cached content.
Install the latest version of Oomph (Eclipse Installer).

Reference: Set up the Toolkit