JAX-RS component must not be registered more than once on javax.ws.rs.core.Configurable instances

public class ProviderRegistrationTest { public static class MyFeature implements Feature { @Override public boolean configure(FeatureContext featureContext) { // MyFilter instance will be registered third on the same // featureContext even if // featureContext.getConfiguration().isRegistered(MyFilter.class)==true featureContext.register(new MyFilter()); return true; } } public static class MyFilter implements ClientRequestFilter { @Override public void filter(ClientRequestContext clientRequestContext) throws IOException { System.out.println(MyFilter.class.getName()); } } public static void main(String[] args) { Client client = ClientBuilder.newClient(); try { WebTarget webTarget = client .target("http://www.changeit.com"); // MyFeature will be registered third on the same webTarget even if // webTarget.getConfiguration().isRegistered(MyFeature.class)==true webTarget.register(MyFeature.class).register(new MyFeature()).register(new MyFeature()).request().get(); } finally { client.close(); } } }