Java Thread prints even numbers on timer

import java.util.Scanner;

public class ThreadsExample {

// main method of our program

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);



        MyThread oddNumber = new MyThread(1);
        Thread t1 = new Thread(oddNumber);
        t1.start();


    }

}


class MyThread implements Runnable {

    private int timer;
    private int counter = 0;
//constructor

    MyThread(int timer) { //modify here


        this.timer = timer;
//code for constructor goes here

    }

    public void run() {

//the task of the thread goes in here

        for (;;) { //infinte loop

            try {

                Thread.sleep(this.timer*1000);

            } catch (InterruptedException e) {

                return;

            }
            //do something before it sleeps/stops for the time amount of seconds
            System.out.print(counter + " ");
            counter+=2;

        }
    }

}

interface ChairBehaviour{
    public void spin();
}

class Chair implements ChairBehaviour{

//properties / variables

    private String name;

    private String colour;

    private String material;

    private float size;

//constructor

    public Chair(String name, String colour, String material, float size) {

        this.name = name;

        this.colour = colour;

        this.material = material;

        this.size = size;

    }

//gets and set methods

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

    public String getColour() {

        return colour;

    }

    public void setColour(String colour) {

        this.colour = colour;

    }

    public String getMaterial() {

        return material;

    }

    public void setMaterial(String material) {

        this.material = material;

    }

    public float getSize() {

        return size;

    }

    public void setSize(float size) {

        this.size = size;

    }

//behaviours

    public void spin() {

        System.out.println("Chair is now spinning");

    }

}