public class Cow {

    private String cowType;
    private String sound;
    private int numMilkings;

    public Cow(){
        this.numMilkings = 0;
        this.cowType = null;
        this.sound = null;
    }

    public Cow (String cowType, String sound) {
        this.numMilkings = 0;
        this.cowType = cowType;
        this.sound = sound;
    }

    public Cow(String cowType, String sound, int numMilikings) {
        this.numMilkings = numMilikings;
        this.cowType = cowType;
        this.sound = sound;
    }

    

    public void setcowType(String cowType) {
        this.cowType = cowType; 
    }

    public String getcowType() {
        return cowType; 
    }

    public void toString() {

    }

    public static void main(String[] args) {
        Cow firstCow = new Cow("holstein", "moo");
        Cow secondCow = new Cow();
        Cow thirdCow = new Cow("holstein", "moo", 100);
        firstCow.setcowType("a"); 
        firstCow.getcowType(); 
        System.out.println(firstCow.getcowType());
    }
}
Cow.main(null)
a