Dependency Injection

• With DI , objects are given their dependencies at creation time by some third party that coordinates injected object in the system. Objects are not expected to create or obtain their dependencies.
• Depedency injection makes the code and object loosely coupled.
• Tightly couples code is difficult to change, test and maintain.
• Depecency Injection is about, object are provided their depedent object by some third party. 
• This third party coordinates the objects in the system.
• The depedencies are not created by the object which need them.
• The depedencies are provided to the object which need them.
• DI binds components of system loosely.
• Two ways DI can be possible
• 1) Using Constructor
• 2) Using setter method