code: public Object put(Object key, Token value) throws ObjectManagerException {
          AbstractMapEntry entry = rbInsert(key);
          Object result = entry.value;
          entry.value = value;
          return result;
      }
docs: Maps the specified key to the specified value.
  
  @param key the key
  @param value the value
  
  @return the value of any previous mapping with the specified key or null
  if there was no mapping
  
  @exception ClassCastException
  when the key cannot be compared with the keys in this
  TreeMap
  @exception NullPointerException
  when the key is null and the comparator cannot handle null
  @throws ObjectManagerException