<!--?xml version="1.0" encoding="UTF-8"?-->
<beans:beans xmlns="http://www.springframework.org/schema/security"
             xmlns:beans="http://www.springframework.org/schema/beans"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
           http://www.springframework.org/schema/security
           http://www.springframework.org/schema/security/spring-security.xsd">

    <http create-session="always"
        use-expressions="true"
        authentication-manager-ref="authenticationManager"
        entry-point-ref="authenticationEntryPoint">
        <csrf disabled="true" />
        <intercept-url pattern="/**" access="hasRole('USER')" />
        <form-login authentication-success-handler-ref="customAuthenticationSuccessHandler" />
        <logout />
    </http>

    <authentication-manager alias="authenticationManager">
        <authentication-provider user-service-ref="userDao"></authentication-provider>
    </authentication-manager>

</beans:beans>

@Component
public class CustomEntryPoint implements AuthenticationEntryPoint {

    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException authException) throws IOException, ServletException {
        System.out.println("Entering commence due to failed Authentication");
        response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Unauthorized Access!");
    }

}

public class UserDao implements UserDetailsService {

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {

        String password = readPasswordFromFileOrDatabase(username);

        if (password == null) throw new UsernameNotFoundException("failure");
        return User.withUsername("user").password(password).authorities("ROLE_USER").build();
    }

    private String readPasswordFromFileOrDatabase(String username) {
        if (username.equals("user")) return "q";
        return null;
    }


}

String plainClientCredentials="myusername:mypassword";