I don't feel right at all.

So what is an instance?

Instances are made from classes, so don't overwhelm them with the previous explanation.

Instances are created with the new keyword, and variables and methods can be operated independently.

I will write

I want you to swallow one setting. Let's prepare a class with the theme of digital student ID and generate an instance of it.

The student ID class Digital Student Card created here has a student ID number num and a student name name in the field.

class DigitalStudentCard{
  //Student number
  int num;

  //name
  String name;

  //Method for output (introduce yourself)
  String getSelfIntroduction(){
    return "Student number: " + num + "name: " + name);
  }
}

Let's use this class.

class UseClass{
  public static void main(String[] args){

    //Instance generation
    DigitalStudentCardtanaka tanaka = new DigitalStudentCard();

    //Assign to instance variable
    tanaka.num = 118114;
    tanaka.name = "Kakuei Tanaka";


    //Create another instance
    DigitalStudentCardnoguchi noguchi = new DigitalStudentCard();

    //Assign to the variable of the newly created instance
    noguchi.num = 118514;
    noguchi.name = "Hideyo Noguchi";

    //output
    System.out.println(tanaka.getSelfIntroduction);
        //Student number:118114 Name:Kakuei Tanaka

    System.out.println(noguchi.getSelfIntroduction);
        //Student number:118514 Name:Hideyo Noguchi

  }
}

Roughly, I issued a student ID card for Kakuei Tanaka and Hideyo Noguchi. By doing this, I think it will be easier to understand that multiple variables are connected and related.

This would create tanakaName and noguchiName and mess up the code if you didn't use the class ... It's horrifying.

Like this, many of the features I'm about to explain are to make the code easier to read, cleaner, and simpler </ b>. The more you use it, the easier it will be to write code, so let's remember it more and more.

if(tanaka == noguchi){
  System.out.println("Same instance");
}else{
  System.out.println("Different instance");
}


/*Execution result*/
// >>Different instance