Using Injection it is possible to make a change to the implementation of an Objective-C class and have it take effect as soon as the class is saved without having to restart an application. This miracle works for OS X and iOS applications in the simulator and on iOS devices.
Injection works by converting your classes into categories using a small set of preprocessor macros. This category can then be loaded at run time using a bundle. As Objective-C "binds" at runtime it will always chose the new implementation of the class over that which the application was last built with.
To download Injection for Xcode for evaluation now click here.