Result of returning null or throwing an exception

svn path=/trunk/; revision=445
diff --git a/src/jsr311-api/src/javax/ws/rs/ext/ExceptionMapper.java b/src/jsr311-api/src/javax/ws/rs/ext/ExceptionMapper.java
index 0a1e58b..a2e9276 100644
--- a/src/jsr311-api/src/javax/ws/rs/ext/ExceptionMapper.java
+++ b/src/jsr311-api/src/javax/ws/rs/ext/ExceptionMapper.java
@@ -25,7 +25,10 @@
 public interface ExceptionMapper<E> {
 
     /**
-     * Map an exception to a {@link javax.ws.rs.core.Response}.
+     * Map an exception to a {@link javax.ws.rs.core.Response}. Returning 
+     * {@code null} results in a {@link javax.ws.rs.core.Response.Status#NO_CONTENT}
+     * response. Throwing a runtime exception results in a 
+     * {@link javax.ws.rs.core.Response.Status#INTERNAL_SERVER_ERROR} response
      * @param exception the exception to map to a response
      * @return a response mapped from the supplied exception
      */