All language subtitles for 036 Primitive vs. Class Type_en

What if I told you that almost everything in Java is an object, I'm going to circle back to the statement

because it's pretty bold.

First, you need to learn the difference between primitive versus class types.

Primitive types are the most basic types of data.

Int double boolean car.

A variable of the primitive type stores, a value directly.

Remember, this primitives represent a value, nothing more like the boolean true, or the number six

primitives cannot be No.

They have no methods.

Class types, also known as reference types, are classes that you can create objects from.

Dealership and car were class types from which we created dealership and car objects.

Remember this, a class type variable points to an object.

It can be no.

And it can call methods from middle class.

Here's a table that summarizes primitive versus class types.

It's in your cheat sheet.

Now, here's a fun fact for you, string is a class type.

First, ask yourself why String capitalized because string is actually a class and class names, as

you know, start with a capital letter Kemel case.

So according to our table string variables, should story reference that points to an object.

And guess what they do?

When you define a string variable, you're actually creating an object of the string class, the variable

stories, a reference that points to a string object.

And it follows that when you said a string variable equal to another, it copies the reference inside

both variables share a reference to the same string object.

Wait a second.

Shouldn't we worry about the reference trap?

Nope.

When you assign the variable and you string, it equals a brand new string object.

In other words, the reference trap doesn't apply, so you don't have to worry.

Back to our table, string variables can be know there are many methods we can call from the string

class.

Try calling them yourself from a random string and see what they do.

Skinner is also a class type that you've seen many times.

So according to our table Skinner variables should story reference that points to an object they do

when you define a scanner variable, you're creating a new object of the scanner class.

The scanner variable can indeed be no.

And there are many methods we can call from the scanner class.

In fact, we've been using them all along, like next int next, double next, long, next and next

line.

These are all methods that are defined in the scanner class, which you can call from your scanner object.

Let's talk about the null value I mentioned earlier that primitive variables cannot be null.

Variables, objects can be no.

No, only applies when memory size is not fixed, primitive types have a fixed memory size and as four

bytes long is eight bytes.

Class types don't have a fixed memory, an object with 20 fields takes up more memory than an object

with one.

Generally speaking.

An array of 50 elements is going to take up more memory than an array with one.

For this reason, primitives cannot be null and class types can be.

By the way, arrays are also objects as well.

When you create a new era, you're creating a new object of the array class that can store elements.

Everything is just happening behind the scenes.

That being said, almost everything in Java is a class variable, an object.

As long as it stores a reference, can be no can call methods, then it's a class variable.

In this lesson, you learn to tell the difference between a primitive type and a class type, a primitive

represent value and nothing more.

It cannot be, no, and it doesn't have methods.

Examples of primitive types are Ent., long car and boolean.

A class variable story, a reference it can be no, and it can call methods, examples of class types

that we created objects from our scanner dealership and car.