java - Difference between Inversion of Control & Dependency Injection

These are patterns to achieve loose coupling in java
programming

DI(Dependency
Injection):
Dependency injection is a pattern used to create
instances of objects
that other objects rely upon without knowing at compile
time
which class will be used to provide that functionality or simply the way
of injecting properties to an object is called dependency
injection.

We have three types of
Dependency
injection

1. Constructor
   Injection


2. Setter/Getter Injection
   


3. Interface
   Injection

Spring will
support only Constructor Injection and Setter/Getter Injection.

IOC(Inversion Of
Control):
Giving control to the container to create and inject
instances of objects that your application depend upon, means instead of you are
creating an object using the new operator, let the container do
that for you.
Inversion of control relies on dependency injection because a
mechanism is needed in order to activate the components providing the specific
functionality

The two concepts work together in
this way to allow for much more flexible, reusable, and encapsulated code to be written.
As such, they are important concepts in designing object-oriented
solutions.

Example for Dependency
injection

Previously we are
writing code like
this

Public
            MyClass{
 DependentClass dependentObject
 /*
 At somewhere
            in our code we need to instantiate 
 the object with new operator inorder to
            use it or perform some method.
 */ 
 dependentObject= new
            DependentClass();

            dependentObject.someMethod();
}

With
Dependency injection, the dependency injector will take off the instantiation for us

Public MyClass{
 /*
            Dependency injector will instantiate object*/
 DependentClass
            dependentObject

 /*
 At somewhere in our code we perform
            some method. 
 The process of instantiation will be handled by the dependency
            injector

 */ 


            dependentObject.someMethod();
}

The
above process of giving the control to some other (for example the container) for the
instantiation and injection can be termed as Inversion of
Control

You can read more on
dependency injection and IOC in my answer :- You can find advantages and applications of
the concepts here.

href="https://stackoverflow.com/questions/130794/what-is-dependency-injection/47090662#47090662">What
is dependency injection?