### Question:
HadoopGroupProviderDeploymentContributor extends AbstractIdentityAsserterDeploymentContributor { @Override public String getName() { return HADOOP_GROUP_PROVIDER; } HadoopGroupProviderDeploymentContributor(); @Override String getName(); @Override void contributeFilter( DeploymentContext context, Provider provider, Service service,
      ResourceDescriptor resource, List<FilterParamDescriptor> params ); @Override List<FilterParamDescriptor> buildFilterInitParms(Provider provider,
      ResourceDescriptor resource, List<FilterParamDescriptor> params); static final String HADOOP_GROUP_PROVIDER; }### Answer:
@Test public void testServiceLoader() throws Exception { ServiceLoader<ProviderDeploymentContributor> loader = ServiceLoader .load(ProviderDeploymentContributor.class); Iterator<ProviderDeploymentContributor> iterator = loader.iterator(); assertThat("Service iterator empty.", iterator.hasNext()); while (iterator.hasNext()) { Object object = iterator.next(); if (object instanceof HadoopGroupProviderDeploymentContributor) { return; } } fail("Failed to find " + HadoopGroupProviderDeploymentContributor.class.getName() + " via service loader."); }