This is a client for OpenShift written in java. It pretty much offers all features that are currently available in the rhc-* command line tools (create/rename a domain, create/destroy applications, list all existing applications, available cartridges, embed cartridges etc.). This is the client that is used in JBoss Tools for OpenShift.
An exemplary usage of the client may look like the following:
final IOpenShiftConnection connection =
new OpenShiftConnectionFactory().getConnection("myApplicationId", "user", "password");
IUser user = connection.getUser();
IDomain domain = user.createDomain("myDomain");
IApplication as7Application = domain.createApplication("myApplication", ICartridge.JBOSSAS_7);
IEmbeddedCartridge mySqlCartridge = as7Application.addEmbeddableCartridge(IEmbeddableCartridge.MYSQL_51);
String unstructuredCredentials = mySqlCartridge.getCreationLog();
String mySqlConnectionUrl = mySqlCartridge.getUrl();
You may either build from source using maven (mvn clean package) or get the prebuilt artifact from the maven central.