What happens when you create a new object?

Question

Ok, so what happens when you do this.

A a1=new A();

A a2=new A();

A a3=new A();

I upload two pictures on how I imagine it being like. Can you

Answer 1

First picture is true for Strings( due to string pooling, an optimisation for strings known to be identical at compile time):

String a1="s";
String a2="s";
String a3="s";

The second one is true for:

A a1=new A();
A a2=new A();
A a3=new A();

If you want behaviour like String has - you should implement Flyweight pattern.

Answer 2

The second picture is correct. Each of the three statements is creating a reference (A a1 =), and an actual object in memory (new A()). Throw out the first picture :)

Answer 3

Go through the images, hope this helps.

Answer 4

Whenever you see a

ABC a1 = new ABC();

it means a new object is created and using a1 you can access it.

It is exactly similar to going to a bike shop and aking them to get a *new bike *. Every time you say new they will get a new bike for you.

Meaning of both sides:

Right side means you have a new object of type on the right side.

The left side says you want to keep a variable of type on the left side.

So you can have different types of both sides but there is a contract or condition that you have to take care. The condition is that the type on the left side should be either a super class of the type on the right side or the left side is an interface and the right side type implements it.

Example:

A a1 = new AB();
A a2 = new BC();

and both AB and BC either are subclass of A or A is an interface which will be implemented.

Now after creating an object when you assign it to the left side is exactly similar to having a baloon (newely created object) and attaching a string (a1) to it. This way you can attach multiple string to one baloon i.e.,

A a1 = new A();
A a2 = a1;

Bithe a1 and a2 point to the same object.