DI meaning in Computing ?

In software engineering, dependency injection is a technique in which an object receives other objects that it depends on, called dependencies. Typically, the receiving object is called a client and the passed-in ('injected') object is called a service. The code that passes the service to the client is called the injector. Instead of the client specifying which service it will use, the injector tells the client what service to use. The 'injection' refers to the passing of a dependency (a service) into the client that uses it.

The service is made part of the client's state. Passing the service to the client, rather than allowing a client to build or find the service, is the fundamental requirement of the pattern.

The intent behind dependency injection is to achieve separation of concerns of construction and use of objects. This can increase readability and code reuse.

Dependency injection is one form of the broader technique of inversion of control. A client who wants to call some services should not have to know how to construct those services. Instead, the client delegates to external code (the injector). The client is not aware of the injector. The injector passes the services, which might exist or be constructed by the injector itself, to the client. The client then uses the services.

This means the client does not need to know about the injector, how to construct the services, or even which services it is actually using. The client only needs to know the interfaces of the services, because these define how the client may use the services. This separates the responsibility of 'use' from the responsibility of 'construction'.