code: protected static ModuleAggregate getModuleAggregate(String moduleID) {
          ModuleAggregate aggregate = (ModuleAggregate) moduleAggregates.get(moduleID);
          if (aggregate != null)
              return aggregate;
          // need to create it - synchronized
          synchronized (moduleAggregates) {
              aggregate = (ModuleAggregate) moduleAggregates.get(moduleID);
              if (aggregate != null)
                  return aggregate;
              PmiModuleConfig config = getConfig(moduleID);
              if (config == null)
                  return null;
              aggregate = new ModuleAggregate(moduleID);
              moduleAggregates.put(moduleID, aggregate);
              return aggregate;
          }
      }
docs: create it if not there - synchronized