# Understand Adoption Barriers

What is the one key aspect of making your APIs reusable? Simply put – reducing the barriers to adoption. It matters because your target audience – architects, developers, and project managers – are all trying to deliver value to their clients. Iteration after iteration. Here are specific strategies to reduce the adoption barriers:

1. Make the public API as intention revealing as possible. Looking at the public interface it must be very clear and unambiguous what the purpose and scope is of the reusable capability.
2. Provide [Builder](http://en.wikipedia.org/wiki/Builder_pattern) or [abstract factory](http://en.wikipedia.org/wiki/Abstract_factory_pattern) APIs to stitch together complex object graphs in a simple  fashion. Make it very easy to wire up the default behaviour and provide hooks to replace specific bits of behaviour that is varying. For example – if saving to a file is a default, provide alternative implementations or an interface hook for your client to inject a custom one.
3. Make it easy to integrate the capability with other complimentary APIs. These could be in-house, open-source, or vendor APIs – key is – if they are likely to co-exist in a solution, make it simple to wire them together. If your developers use Spring for dependency injection, make your components easy to work with when it. Ditto for in-house frameworks that your teams use heavily.
4. For reusable assets that perform orchestration logic provide hooks for injecting custom logic before / after your API behaviour This will be useful for initializing / cleanup logic – specially with legacy components that may need a bespoke set of steps to start them or free up resources on shutdown.
5. Provide Null and/or mocking friendly implementations for testability. Your clients need to test their code via automated tests and so do you as the provider – both these needs are met via testable providers. Make it easy for developers to use them with [JUnit](https://github.com/junit-team/junit/wiki/Getting-started) and make it hard for them to bypass the public APIs.
