Sending Custom JSON from Java class in case of aut

Question

@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class SecurityConfig extends WebSecurityConfigurerAdapter{

    @Autowired
    private RESTAuthenticationEntryPoint authenticationEntryPoint;
    @Autowired
    private RESTAuthenticationFailureHandler authenticationFailureHandler;
    @Autowired
    private RESTAuthenticationSuccessHandler authenticationSuccessHandler;

    @Autowired
    private UserDetailsService userDetailsService;

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(userDetailsService).passwordEncoder(new BCryptPasswordEncoder());
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.sessionManagement()
                .sessionCreationPolicy(SessionCreationPolicy.STATELESS)
                .and()
                .authorizeRequests()
                .antMatchers("/hello").permitAll()
                .antMatchers("/secure/hello").authenticated()
                .and()
                .httpBasic()
                .realmName("KS TEST")
                .and()
                .csrf()
                .disable();

        http.exceptionHandling().authenticationEntryPoint(authenticationEntryPoint);
        http.formLogin().successHandler(authenticationSuccessHandler);
        http.formLogin().failureHandler(authenticationFailureHandler);
        http.logout().logoutSuccessUrl("/");

    }

    @Override
    @Bean
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }
}

I have pasted part of above code. I also extended three classes and injected them as bean AuthenticationEntryPoint, SimpleUrlAuthenticationFailureHandler, SimpleUrlAuthenticationSuccessHandler thinking I could extend those and try to get custom error message in case of auth failure. I get the standard spring auth failure in my REST API that works perfectly but I want to define my own class that I want to send as response at auth layer even before the resource endpoint comes into play. Like my own custom class with my own data members. Currently I get the default error in case of wrong auth

{"timestamp":1469955305299,"status":401,"error":"Unauthorized","message":"Bad credentials","path":"/secure/hello"}

This is how i execute the rest call with wrong pwd

//REST API execution example
curl  -v -u mickey:cheesee http://localhost:8080/secure/hello

If i give the right pwd things work as expected. However in wrong one, say I want to have a class that I can populate and that becomes json reponse at the auth layer. Can someone tell me what I need to do?