Merge pull request #347 from ttulka/master

a comment added to explain the use of HashMap

JSONObject.java

@@ -164,6 +164,12 @@ public String toString() {
      * Construct an empty JSONObject.
      */
     public JSONObject() {
+        // HashMap is used on purpose to ensure that elements are unordered by 
+        // the specification.
+        // JSON tends to be a portable transfer format to allows the container 
+        // implementations to rearrange their items for a faster element 
+        // retrieval based on associative access.
+        // Therefore, an implementation mustn't rely on the order of the item.
         this.map = new HashMap<String, Object>();
     }
 
@@ -216,15 +222,15 @@ public JSONObject(JSONTokener x) throws JSONException {
                 key = x.nextValue().toString();
             }
 
-// The key is followed by ':'.
+            // The key is followed by ':'.
 
             c = x.nextClean();
             if (c != ':') {
                 throw x.syntaxError("Expected a ':' after a key");
             }
             this.putOnce(key, x.nextValue());
 
-// Pairs are separated by ','.
+            // Pairs are separated by ','.
 
             switch (x.nextClean()) {
             case ';':