Refactoring to remove remaining circular dependencies indicated by structure101.

ldap/src/main/java/org/springframework/security/ldap/userdetails/LdapUserDetailsService.java

@@ -1,10 +1,13 @@
 package org.springframework.security.ldap.userdetails;
 
+import java.util.Collection;
+
 import org.springframework.ldap.core.DirContextOperations;
+import org.springframework.security.core.GrantedAuthority;
+import org.springframework.security.core.authority.AuthorityUtils;
 import org.springframework.security.core.userdetails.UserDetails;
 import org.springframework.security.core.userdetails.UserDetailsService;
 import org.springframework.security.core.userdetails.UsernameNotFoundException;
-import org.springframework.security.ldap.authentication.NullLdapAuthoritiesPopulator;
 import org.springframework.security.ldap.search.LdapUserSearch;
 import org.springframework.util.Assert;
 
@@ -16,8 +19,8 @@ import org.springframework.util.Assert;
  * @author Luke Taylor
  */
 public class LdapUserDetailsService implements UserDetailsService {
-    private LdapUserSearch userSearch;
-    private LdapAuthoritiesPopulator authoritiesPopulator;
+    private final LdapUserSearch userSearch;
+    private final LdapAuthoritiesPopulator authoritiesPopulator;
     private UserDetailsContextMapper userDetailsMapper = new LdapUserDetailsMapper();
 
     public LdapUserDetailsService(LdapUserSearch userSearch) {
@@ -42,4 +45,10 @@ public class LdapUserDetailsService implements UserDetailsService {
         Assert.notNull(userDetailsMapper, "userDetailsMapper must not be null");
         this.userDetailsMapper = userDetailsMapper;
     }
+
+    private static final class NullLdapAuthoritiesPopulator implements LdapAuthoritiesPopulator {
+        public Collection<GrantedAuthority> getGrantedAuthorities(DirContextOperations userDetails, String username) {
+            return AuthorityUtils.NO_AUTHORITIES;
+        }
+    }
 }