LDAP properties binding fail
<p>I have a bean with LDAP properties for authentication manager. </p>

<p>When I'm explicitly putting properties in there it does work, but when I started to use <code>.properties</code> file, it gives me an error.</p>

<blockquote>
  <p>Failed to parse DN; nested exception is
  org.springframework.ldap.core.TokenMgrError: Lexical error at line 1,
  column 1. Encountered: "$" (36), after :</p>
</blockquote>

<p>What do I do wrong?</p>

<pre><code>@EnableWebSecurity
public class SecurityConfig {

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        auth.ldapAuthentication()
            .userSearchFilter("${ldap.user_search_filter}")
            .userSearchBase("${ldap.user_search_base}")
            .groupSearchFilter("${ldap.group_search_filter}")
            .groupSearchBase("${ldap.group_search_base}")
            .groupRoleAttribute("${ldap.group_role_attribute}")
            .rolePrefix("${ldap.role_prefix}")
            .contextSource().ldif("${ldap.ldif_path}")
            .root("${ldap.root}");
    }
    .....
}
</code></pre>