Safe way of adding resource to the resource set

AddingResourceToReasourceset.java

// Get the URI to the resource
final URI uri = resource.getURI();
// Get the resource resolved by the URI. Do not load the resource, only get one if exists
final Resource r = resourceSet.getResource(uri, false);
if (r != null) {
  // Add the resource to the resourceset
  resourceSet.getResources().add(resource);
}