improved exception message when the type of a json descriptor entry is not provided

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1067887 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/dependencymanager/runtime/src/main/java/org/apache/felix/dm/runtime/DescriptorParser.java b/dependencymanager/runtime/src/main/java/org/apache/felix/dm/runtime/DescriptorParser.java
index 7a60181..24b0979 100644
--- a/dependencymanager/runtime/src/main/java/org/apache/felix/dm/runtime/DescriptorParser.java
+++ b/dependencymanager/runtime/src/main/java/org/apache/felix/dm/runtime/DescriptorParser.java
@@ -53,11 +53,17 @@
         JSONMetaData serviceMetaData = new JSONMetaData(json);
 
         String type = (String) json.get("type");
+        if (type == null)
+        {
+            throw new IllegalArgumentException("Invalid descriptor"
+                    + ": no \"type\" parameter found in first line");
+        }
+
         AbstractBuilder builder = m_builders.get(type);
         if (builder == null)
         {
             throw new IllegalArgumentException("Invalid descriptor"
-                    + ": no \"type\" parameter found in first line");
+                    + ": invalid \"type\" parameter found in first line");
         }
 
         // Parse the rest of the lines (dependencies)