Где я ошибся?

package lab2_3;
 
import java.util.Scanner;
 
class MainClass{
    public static void main(String[] args) {
        Scanner in = new Scanner (System.in);
        int x1 = in.nextInt();
        int y1 = in.nextInt();
        int x2 = in.nextInt();
        int y2 = in.nextInt();
        in.close();
        Rook rook = new Rook(x1 , y1, x2, y2);
        Queen queen = new Queen(x1 , y1, x2, y2);
        System.out.println(rook);
        System.out.println(queen);
    }
}
 
public abstract class Piece {
    int x1, x2, y1, y2;
    public abstract void isLegalMove();
    
    public Piece(int x1, int y1, int x2, int y2) {
        this.x1 = x1;
        this.y1 = y1;
        this.x2 = x2;
        this.y2 = y2;
    }
}
 
class Rook extends Piece{
    public Rook(int x1, int y1, int x2, int y2) {
        super(x1, y1, x2, y2);
    }
    
    public void isLegalMove() {
        if (x1 == x2 || y1 == y2) {
            System.out.println("That's right move!");
        }
        else{
            System.out.println("You can't play the chess ='(");
        }
    }
    
}
 
class Queen extends Piece{
    public Queen(int x1, int y1, int x2, int y2) {
        super(x1, y1, x2, y2);
    }
    
    public void isLegalMove() {
        if (x1 == x2 || y1 == y2 || Math.abs(x1 - x2) == Math.abs(y1 - y2)) {
            System.out.println("That's right move!");
        }
        else{
            System.out.println("You can't play the chess ='(");
        }
    }
}

public class Helper {
 
    public static void main(String[] args) {
        Chessman blackQueen = new Queen(5,5);
        blackQueen.makeMove(5,7);
        blackQueen.makeMove(5,4);
    }
}
abstract class Chessman {
    protected abstract boolean isLegalMove(int newPosX, int newPosY);
    public abstract void makeMove(int newPosX, int newPosY);
    void printRezultMove(boolean isOk){
        if (isOk) System.out.println("That's right move!");
        else System.out.println("That's invalid move!");
    }
}
 
class Queen extends Chessman {
    private int xInit;
    private int yInit;
 
    Queen(int xInit, int yInit) {
        this.xInit = xInit;
        this.yInit = yInit;
    }
 
    @Override
    public boolean isLegalMove(int newPosX, int newPosY) {
        return Math.abs(xInit - newPosX) == 1 || Math.abs(yInit - newPosY) == 1;
    }
 
    @Override
    public void makeMove(int newPosX, int newPosY) {
        boolean tmp = isLegalMove(newPosX, newPosY);
        if (tmp) {
            xInit = newPosX;
            yInit = newPosY;
        }
        printRezultMove(tmp);
    }
}