Declaration and initialization of an object compared to a data type?-CodePudding

In Java, is declaring/initializing primitives the same as declaring/initializing new objects? Primitives can be initialized with a literal, but what is the format for objects.

CodePudding user response：

It's not quite the same but very similar. Both follow the rule:

datatype variablename = value;

Examples:

int i = 0;
Car c = new Car();

Primitive types have literals like numbers (int, double...), boolean (true/false) or a character (char). Objects are objects of a class. A class is a template for something and while initializing that template a new object of that class is created. In the example above c is an object of the class Car.

The class has to exist. The are may classes delivered by Java like String:

String name = new String("John Doe");
String name = "John Doe";

But you can make your own classes, e.g..

public class MyClass {
    private int i;

    public MyClass(int i) {
        this.i = i;
    }
}

You can read up on classes e.g. here. Classes are one of the main concepts of Object-oriented programming (OOP).

CodePudding user response：

Nope.

You use new to initialize an Object and as you stated you use a literal to initialize a primitive.

I suggest checking out https://docs.oracle.com/javase/tutorial/java/index.html for a helpful guide.