code: public synchronized Object remove(String key) {
          Object retVal;
  
          retVal = primaryTable.remove(key);
          if (retVal == null) {
              retVal = secondaryTable.remove(key);
              if (retVal == null) {
                  return tertiaryTable.remove(key);
              }
          }
          return retVal;
      }
docs: Remove an object from the Cache.
  
  @param key the key of the entry to be removed
  @return the previous value associated with key, or null if there was none