Response for preflight has invalid HTTP status code 401 - Spring

This could be very late but this could solve some ones problem, after long hours i found the answer

public class SecurityConfig extends WebSecurityConfigurerAdapter
{
    @Override
    public void configure( WebSecurity web ) throws Exception
    {
        web.ignoring().antMatchers( HttpMethod.OPTIONS, "/**" );
    }
}

Refer https://stackoverflow.com/a/45830981/3724760

avoid filtering and set status 200 when http method is OPTIONS

if("OPTIONS".equalsIgnoreCase(request.getMethod())) {
    response.setStatus(HttpServletResponse.SC_OK);
} else {
    chain.doFilter(req, res);
}

If there is anyone getting into the similar situation working around with Spring Boot, Spring Security and clients like angular 2/4, I've posted the findings here.

For those who are looking for a short answer, you have to configure two things:

1. With Spring Boot, the recommended way to enable global CORS is to declare within Spring MVC and combined with fine-grained @CrossOrigin configuration as:

   @Configuration
   public class CorsConfig {
   
       @Bean
       public WebMvcConfigurer corsConfigurer() {
           return new WebMvcConfigurerAdapter() {
               @Override
               public void addCorsMappings(CorsRegistry registry) {
                   registry.addMapping("/**").allowedMethods("GET", "POST", "PUT", "DELETE").allowedOrigins("*")
                           .allowedHeaders("*");
               }
           };
       }
   }
   

2. Then, while working with Spring Security, you have to enable CORS at Spring Security level as well to allow it to leverage the configuration defined at Spring MVC level as:

   @EnableWebSecurity
   public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
   
       @Override
       protected void configure(HttpSecurity http) throws Exception {
           http.cors().and()...
       }
   }
   

Cheers!!!