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

public static final class MyFeature implements Feature { @Override public boolean configure(FeatureContext featureContext) { featureContext.register( new MyFilter()); featureContext.register( new MyFilter()); //Should be rejected at runtime return true ; } } public static final class MyFilter implements ClientRequestFilter { @Override public void filter(ClientRequestContext clientRequestContext) throws IOException { System .out.println(MyFilter. class. getName()); } } @Test public void test() { Client client = ClientBuilder.newClient(); try { WebTarget webTarget = client.target( "http: //www.changeit.com" ); webTarget.register(MyFeature.class).request().get(); } finally { client.close(); } }