title: warnings after updating to xcode 4.4.1 for RestKit
body: <p>When I updated Xcode to 4.4.1 It gives me 22 warning for using RestKit Library. The error was like this: </p>
  
  <pre><code>Direct access to objective-c's isa is deprecated in favor of object_setClass() and object_getClass()
  </code></pre>
  
  <p>I fixed 18 warnings by replacing:</p>
  
  <p>Replace <code>%lu</code> with <code>%u</code></p>
  
  <p>Replace <code>object-&gt;isa</code> with <code>object_getClass(object)</code> </p>
  
  <p>Replace <code>keyObject-&gt;isa</code> with <code>object_getClass(keyObject)</code></p>
  
  <p>There are 4 more warnings that I cannot fix it, here are the warnings following by its descriptions:</p>
  
  <p>file Name 1: RKManagedObjectMappingOperation.m
  Warning Line1:</p>
  
  <pre><code>NSAssert(mapping, @"Attempted to connect relationship for keyPath '%@' without a relationship mapping defined.");
  </code></pre>
  
  <p>Warning Description1:</p>
  
  <pre><code>more '%' conversations than data arguments
  </code></pre>
  
  <p>File Name2: RKReachabilityObserver.m
  Warning Line2: </p>
  
  <pre><code>return [NSString stringWithFormat:@"&lt;%@: %p host=%@ isReachabilityDetermined=%@ isMonitoringLocalWiFi=%d reachabilityFlags=%@&gt;",
              NSStringFromClass([self class]), self, self.host, self.isReachabilityDetermined ? @"YES" : @"NO",
              self.isMonitoringLocalWiFi ? @"YES" : @"NO", [self reachabilityFlagsDescription]];
  </code></pre>
  
  <p>Warning description2: </p>
  
  <pre><code>format specifies type int but the argument has type NSString
  </code></pre>
  
  <p>File Name3: JSONKit.m
  Warning Line3: </p>
  
  <pre><code>if(JK_EXPECT_F(((id)keys[idx])-&gt;isa != encodeState-&gt;fastClassLookup.stringClass) &amp;&amp; JK_EXPECT_F([(id)keys[idx] isKindOfClass:[NSString class]] == NO)) { jk_encode_error(encodeState, @"Key must be a string object."); return(1); }
  </code></pre>
  
  <p>Warning Description3: </p>
  
  <pre><code>Direct access to objective-c's isa is deprecated in favor of object_setClass() and object_getClass()
  </code></pre>
  
  <p>File Name4: NSManagedObject+ActiveRecord.m
  Warning Line 4: </p>
  
  <pre><code>RKLogError(@"Property '%@' not found in %@ properties for %@", propertyName, [propDict count], NSStringFromClass(self));
  </code></pre>
  
  <p>Warning description4:</p>
  
  <pre><code>format specifies type id but the argument has type NSUInteger
  </code></pre>
  
  <p>How to fix it?</p>