Fixed Integer#to_json going in an infinite recursion.

Closes #3.

src/json/ext/Generator.java

@@ -37,6 +37,16 @@ private Generator() {
         return session.infect(handler.generateNew(session, object, depth));
     }
 
+    /**
+     * Encodes the given object as a JSON string, detecting the appropriate handler
+     * for the given object.
+     */
+    static <T extends IRubyObject> RubyString
+            generateJson(ThreadContext context, T object, IRubyObject[] args) {
+        Handler<? super T> handler = getHandlerFor(context.getRuntime(), object);
+        return generateJson(context, object, handler, args);
+    }
+
     /**
      * Encodes the given object as a JSON string, using the appropriate
      * handler if one is found or calling #to_json if not.

src/json/ext/GeneratorMethods.java

@@ -85,8 +85,7 @@ public static class RbInteger {
         @JRubyMethod(rest=true)
         public static IRubyObject to_json(ThreadContext context,
                 IRubyObject vSelf, IRubyObject[] args) {
-            return Generator.generateJson(context, vSelf,
-                    Generator.GENERIC_HANDLER, args);
+            return Generator.generateJson(context, vSelf, args);
         }
     };