I am using postman to send a username and password **without value** to my server; it's like `username=null` and `password=null`.

![enter image description here](//i.stack.imgur.com/6p9fH.png)

To control the security of my server, I use spring security 3.2. When it receives these credentials spring-security responds with this error.

```
Estado HTTP 500 - Fields must not be empty

java.lang.IllegalArgumentException: Cannot pass null or empty values to constructor
    org.springframework.security.core.userdetails.User.<init>(User.java:99)
    org.springframework.security.core.userdetails.User.<init>(User.java:69)
    com.equifax.product.fraud.applicationprocessing.web.rest.interceptors.security.SecurityAuthenticationProvider.retrieveUser(SecurityAuthenticationProvider.java:59)
    org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider.authenticate(AbstractUserDetailsAuthenticationProvider.java:132)
    org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:156)
    org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:177)
    org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:168)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
    org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)
        org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)

```

I want output JSON with custom message with the error, how can I do that?

This is my security.xml:

```
    <security:http create-session="never" use-expressions="true"
    auto-config="false">

    <security:intercept-url pattern="/application/**"
        access="isFullyAuthenticated()" />
    <security:anonymous />
    <security:http-basic entry-point-ref="securityAccessDeniedEntryPoint" />
    <security:access-denied-handler ref="securityAccessDeniedHandler" />
</security:http>

<security:authentication-manager alias="authenticationManager"
    erase-credentials="false">
    <security:authentication-provider
        ref="genericSecurityAuthenticationProvider" />
</security:authentication-manager>

```

I'am using Spring 3.2