code: @Nonnull
    public final JettyStarter setPort (@Nonnegative final int nPort)
    {
      ValueEnforcer.isGT0 (nPort, "Port");
      m_nPort = nPort;
      return this;
    }
docs: Set the port to be used to run the application. Defaults to
  {@value #DEFAULT_PORT}
  
  @param nPort
  The port to be used. Must be &gt; 0.
  @return this for chaining