code: public Object lookup(String name) throws ObjectNameNotFoundException
      {
          /**
           * Is DB open? ODMG 3.0 says it has to be to call bind.
           */
          if (!this.isOpen())
          {
              throw new DatabaseClosedException("Database is not open. Must have an open DB to call lookup");
          }
          /**
           * Is Tx open? ODMG 3.0 says it has to be to call bind.
           */
          TransactionImpl tx = getTransaction();
          if (tx == null || !tx.isOpen())
          {
              throw new TransactionNotInProgressException("Tx is not open. Must have an open TX to call lookup.");
          }
  
          return tx.getNamedRootsMap().lookup(name);
      }
docs: Lookup an object via its name.
  @param name The name of an object.
  @return The object with that name.
  @exception ObjectNameNotFoundException There is no object with the specified name.
  ObjectNameNotFoundException