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Constructors

Is a special method that is used to initialize objects.

The constructor is called when an object of a class is called it can be used to set initial values for object attributes

Constructor name must match the class name, and can’t have a return type

All classes have constructors by default(if you do not create a class constructor yourself, java creates one for you, then, you are not able to set initial values for object attributes

public class Main{
  int x;
  public Main(){
    x = 5;
  }
  public static void main(String[] args){
    Main myObj = new Main();
    System.out.println(myObj.x);		// output 5
  }
}

Parameters(Constructor)

Can also take parameters, which is used to initialize attrubutes

public class Main{
  int modelYear;
  String modelName;

  public Main(int year, String name){
    modelYear = year;
    modelName = name;
  }

  public static void main(String[] args){
    Main myCar = new Main(1969, "Mustang");
    System.out.println(myCar.modelYear + " " + myCar.modelName); //output 1969 Mustang
  }
}