Why Private Property Rather Than Public Property In Java?

Why To Set A Property To Be Private Rather Than To Be Public Directly In Java?

You will use like this:

class Door{    private double width;    private double height;    public setWidth(double width){        this.width = width;    }    public getWidth(){         return width;    }    public setHeight(double height){        this.height = height;    }    public getHeight(){         return height;    }}

You won’t use like this:

class Door{    public double width;    public double height;}

WHY?–>Principle: Package

I’ll show this to you in three case:

• The first:
  You must make the property of width be private and get it by method getWidth() when the width of the door can be get only but can not be set.

class Door{    private double width;    private double height;    //public setWidth(double width){    //    this.width = width;    //}    public getWidth(){         return width;    }    public setHeight(double height){        this.height = height;    }    public getHeight(){         return height;    }}

• The second:
  You must make the property of width be private and set it by method setWidth() when the width of the door is limited.

    public setWidth(double width){        if(width <= 10){    //width[10, 210]            width = 10;        } else if(width >= 120){            width = 120;        } else {            this.width = width;                }    }    Door myDoor = new Door();    myDoor.setWidth(-12);    myDoor.setWidth(132);    myDoor.setWidth(98);

• The three:
  You can change it by extending the class easily if the size of the width must change.