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Final/Const in Java

java-display

May 2, 2017
Published By : Pratik Kataria
Categorised in:

Why use final / constant variable?

  • Currently in Java, developers create constant variables i.e. variables whose value don’t change with the help of ‘final’ keyword.
  • Such constant variables are named in all uppercase letters.
  • The use of these variables makes the coding easier and the code robust.
  • If you by mistake write incorrect value for constant variable then it is easy to fix as the change needs to be done only once in declaration.

Bike.java file in folder path: K:\Final\model

package model;

public class Bike {

	public static final String HONDA = "Honda";
	public static final String YAMAHA = "Yamaha";

	private String name = "Honda";
	private long color = 0x2E0456;
	private int gearOrNot = 1;

	public Bike() {} //does nothing but must be defined and public

	public Bike(String name, long color, int gearOrNot) {
		this.name = name; 
		this.color = color;
		this.gearOrNot = gearOrNot;
	}

	public String getName() { return name; }

	public long getColor() { return color; }

	public int getGearOrNot() { return gearOrNot; }

}

 Vehicle.java file in folder path: K:\Final

import model.Bike;
import java.util.List;
import java.util.ArrayList;

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

		List<Bike> bikes = new ArrayList<>();

		bikes.add(new Bike(Bike.HONDA, 0x2E0456, 1));
		bikes.add(new Bike(Bike.YAMAHA, 0x2E0854, 1));
		bikes.add(new Bike(Bike.YAMAHA, 0x2E0555, 1));

		for(Bike b: bikes) {
		 	System.out.println(b.getName() +" " + b.getColor() + " " + b.getGearOrNot());
		}

	}
}

 

Pratik Kataria is a budding programmer, web designer and developer.