anchor.diff:              return localInstance.getMap(configuration.getMapName()).getLocalMapStats().getHeapCost();
           }
       };
  -    if (members.isEmpty()) { // == if no specific memebers defined, apply on all the cluster
  +    if (members.isEmpty()) { // == if no specific members defined, apply on all the cluster
           return executorService.submitToAllMembers(sizeComputation);
       }
       final Set<Member> members = instance.getCluster().getMembers().stream()
  
positive.code: @Service
  public class HazelcastService {
      public HazelcastInstance findInstance(final ClientConfig config) {
          return HazelcastClient.newHazelcastClient(config);
      }
  }
  ----
  
  === The PreDestroy method
  [source,java,indent=0,subs="verbatim,quotes,attributes"]
  ----
  //This execution service will be used in our mapper. So we add it as an attribute
  private transient IExecutorService executorService;
  
  @PreDestroy
  public void close() {
      // Here we shutdown the instance that we have created in the PostConstruct.
      // and we free the executorService reference
      instance.getLifecycleService().shutdown();
      executorService = null;
  }
  ----
  
  === The Assessor method
  [source,java,indent=0,subs="verbatim,quotes,attributes"]
  ----
  @Assessor
  public long estimateSize() {
      // Here we calculate the hole size of all memebers
      return getSizeByMembers().values().stream()
              .mapToLong(this::getFutureValue)
              .sum();
  }
  
  // This method return a map of size by memeber of hazelcast cluster
  private Map<Member, Future<Long>> getSizeByMembers() {
      final IExecutorService executorService = getExecutorService();
      final SerializableTask<Long> sizeComputation = new SerializableTask<Long>() {
  
negative.code:     this(configuration, jsonFactory, jsonb, service, emptyList());
  }
  
  // internal <3>
  protected HazelcastMapper(final HazelcastConfiguration configuration,
          final JsonBuilderFactory jsonFactory,
          final Jsonb jsonb,
  