“Federation is the act of combining data or identities across multiple systems. Federation can be done by a cloud provider or by a cloud broker. A broker has no cloud resources of its own, but matches consumers and providers based on the SLA required by the consumer. The consumer has no knowledge that the broker does not control the resources.” - Cloud computing community

Here is a sample code for creating an AMI from java code, using the Amazon's EC2 aws-java-sdk. I didn't manage to find a good "hello world" example for java, so I post my attempt here. I hope that you can kick-start working on the cloud.
First, you create an instance of the wrapper. Then, you can use it for example like:  createAMInstances(amiId, 1, 3, "mykey", "m1.small", "us-east-1a");

Christos Tranoris, is currently a research fellow of the Network Architectures and Management Group of the Electrical and Computer Engineering Department of University of Patras, which carries out research in the areas of Future Internet, Peer-to-Peer and Network Management while it is currently participating in related EU projects. He holds a diploma since 1999 from the Electrical and Computer Engineering Department at the University of Patras and a phd since 2006 from the same department. His phd was in the area of software processes on modeling and design of industrial applications with the title: A software development process for Industrial applications supported by a CASE tool (CASE: Computer Aided Software Engineering).

Github projects: https://github.com/ctranoris

ORCID: http://orcid.org/0000-0002-3433-037X