Dependency Injection<\/a> is a Software Design Pattern<\/a> that implements Inversion of Control<\/a>. In the paradigm of Object-Oriented Programming<\/a>, it allows a client to receive its dependencies from an external source rather than creating them internally. This technique promotes Loose Coupling<\/a> and significantly improves the ease of Unit Testing<\/a> by allowing developers to inject mock objects.<\/p> The pattern is typically implemented in three ways:<\/p> Modern software development often utilizes a Dependency Injection Container<\/a> to automate these processes. Notable frameworks providing this functionality include the Spring Framework<\/a> for Java, Angular<\/a> for front-end development, and the native container in .NET<\/a>. Industry expert Martin Fowler<\/a> discussed the importance of this pattern in his seminal article<\/a> on the subject. For a broader overview, the Wikipedia page on Dependency Injection<\/a> provides extensive history and context.<\/p>Common Implementation Methods<\/h2>