protected void addAuthenticateHeader(final WebContext context) {
        // set the www-authenticate in case of error
        context.setResponseHeader(HttpConstants.AUTHENTICATE_HEADER, "Basic realm=\"" + realmName + "\"");
    }
<p>addAuthenticateHeader.</p>

@param context a {@link WebContext} object
pac4j-http/src/main/java/org/pac4j/http/client/direct/DirectBasicAuthClient.java