Explain use of Class<?>

svn path=/trunk/; revision=341
diff --git a/src/jsr311-api/src/javax/ws/rs/core/ApplicationConfig.java b/src/jsr311-api/src/javax/ws/rs/core/ApplicationConfig.java
index 0977269..a2cfa45 100644
--- a/src/jsr311-api/src/javax/ws/rs/core/ApplicationConfig.java
+++ b/src/jsr311-api/src/javax/ws/rs/core/ApplicationConfig.java
@@ -27,7 +27,9 @@
     private static final Map<String, String> emptyLanguageMap = Collections.emptyMap();
     
     /**
-     * Get a list of root resource classes. An implementation should warn about
+     * Get a list of root resource classes. Resource classes are not required
+     * to implement any specific interface so the return type is necessarily
+     * loose, nevertheless, implementations should warn about
      * and ignore classes that do not conform to the requirements of root 
      * resource classes.
      * @return a list of root resource classes.
@@ -36,7 +38,9 @@
     public abstract Set<Class<?>> getResourceClasses();
     
     /**
-     * Get a list of provider classes. An implementation should warn about
+     * Get a list of provider classes. There is no common base class or 
+     * interface for providers so the return type is necessarily
+     * loose, nevertheless, implementations should warn about
      * and ignore classes that do not conform to the requirements of a
      * provider. The default implementation returns an empty set.
      * @return a set of provider classes