code: public boolean isInstanceOf(Object obj, Class<?> clz) {
          if (obj == null || clz == null) {
              if (log.isLoggable(Level.FINEST)) {
                  log.finest("isInstanceOf error: obj=" + obj + " clz=" + clz);
              }
              return false;
          }
          return clz.isInstance(obj);
      }
docs: This method determines whether the supplied object is an
  instance of the supplied class/interface.
  
  @param obj The object
  @param clz The class
  @return Whether the object is an instance of the class