//get all active editor references,check if reference is of type java editor
IEditorReference[] ref = PlatformUI.getWorkbench()
.getActiveWorkbenchWindow().getActivePage()
.getEditorReferences();
List<IEditorReference> javaEditors = new ArrayList<IEditorReference>();
for (IEditorReference reference : ref) {
if ("org.eclipse.jdt.ui.CompilationUnitEditor".equals(reference.getId())){
javaEditors.add(reference);
}
}