In computer programming, a software framework is an abstraction in which software providing generic functionality can be selectively changed by additional user-written code, thus providing application-specific software. A software framework is a universal, reusable software environment that provides particular functionality as part of a larger software platform to facilitate development of software applications, products and solutions. Software frameworks may include support programs, compilers, code libraries, tool sets, and application programming interfaces (APIs) that bring together all the different components to enable development of a project or solution. Frameworks contain key distinguishing features that separate them from normal libraries: inversion of control: In a framework, unlike in libraries or normal user applications, the overall program’s flow of control is not dictated by the caller, but by the framework. default behavior: A framework has a default behavior. This default behavior must be some useful behavior and not a series of no-ops. extensibility: A framework can be extended by the user usually by selective overriding or specialized by user code to provide specific functionality. non-modifiable framework code: The framework code, in general, is not supposed to be modified, while accepting user-implemented extensions. In other words, users can extend the framework, but should not modify its code.