public void mouseUp() {
    String qualifiedName=selectedObject.getQualifiedClassName();
    IJavaProject[] projects;
    projects= JavaCore.create(
                ResourcesPlugin.getWorkspace().
                getRoot()).getJavaProjects();
    for (int i= 0; i < projects.length; i++) {
                IJavaProject project= projects[i];
                IType type= project.findType(qualifiedName);
                if (type != null) {
                           JavaUI.openInEditor(type);
                return;
                }
    }
}

Example 3: Implementing behavior of a handle.