public class Application extends SpringBootServletInitializer implements EmbeddedServletContainerCustomizer { 
  @Override 
  protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) { 
    return builder.sources(Application.class); 
  } 
  public static void main(String[] args) { 
    SpringApplication.run(Application.class, args); 
  } 
  @Override 
  public void customize(ConfigurableEmbeddedServletContainer container) { 
    container.setPort(8081); 
  } 
}

server.port=8084