code: public OtpErlangPid whereis(final String name) {
          final OtpMbox m = mboxes.get(name);
          if (m != null) {
              return m.self();
          }
          return null;
      }
docs: Determine the {@link OtpErlangPid pid} corresponding to a registered name
  on this node.
  
  @return the {@link OtpErlangPid pid} corresponding to the registered
  name, or null if the name is not known on this node.