Check out the examples source code in the github repository
The github repository contains the full disclosed source of JCOReflector: a tool able to reflect .NET classes in Java (JVM) to simplify the use of .NET from Java or any other JVM enabled language.
In this basic example you can learn to use a simple .NET c# class from a Java application.
In this example you can see how to integrate WPF and Windows form controls in a Java user interface application.