this obj java meaning

1public class Point {
2    public int x = 0;
3    public int y = 0;
4        
5    //constructor
6    public Point(int x, int y) {
7        this.x = x;
8        this.y = y;
9    }
10}
11

1public class Point {
2    public int x = 0;
3    public int y = 0;
4        
5    //constructor
6    public Point(int a, int b) {
7        x = a;
8        y = b;
9    }
10}
11