code: public void addMetaMethod(MetaMethod method) {
          if (isInitialized()) {
              throw new RuntimeException("Already initialized, cannot add new method: " + method);
          }
  
          final CachedClass declaringClass = method.getDeclaringClass();
          addMetaMethodToIndex(method, metaMethodIndex.getHeader(declaringClass.getTheClass()));
      }
docs: adds a MetaMethod to this class. WARNING: this method will not
  do the neccessary steps for multimethod logic and using this
  method doesn't mean, that a method added here is replacing another
  method from a parent class completely. These steps are usually done
  by initialize, which means if you need these steps, you have to add
  the method before running initialize the first time.
  
  @param method the MetaMethod
  @see #initialize()