code: private void buildImplementedMethodList() {
          Set<TypeMirror> intfacs = utils.getAllInterfaces(typeElement);
          for (TypeMirror interfaceType : intfacs) {
              ExecutableElement found = utils.findMethod(utils.asTypeElement(interfaceType), method);
              if (found != null) {
                  removeOverriddenMethod(found);
                  if (!overridingMethodFound(found)) {
                      methlist.add(found);
                      interfaces.put(found, interfaceType);
                  }
              }
          }
      }
docs: Search for the method in the array of interfaces. If found check if it is
  overridden by any other subinterface method which this class
  implements. If it is not overidden, add it in the method list.
  Do this recursively for all the extended interfaces for each interface
  from the array passed.