En redéfinissant @Override public boolean equals(Object o), en castant o vers la classe cible dans un try/catch(ClassCastException), puis en comparant les champs pertinents

Signature correcte : prend Object (pas Point) pour bien redéfinir Object.equals.

class Point {
    final int x, y;
    Point(int x, int y) { this.x=x; this.y=y; }
    @Override
    public boolean equals(Object o) {
        // ...
    }
}

Caster o vers Point dans un bloc try.

@Override
public boolean equals(Object o) {
    try {
        Point that = (Point) o;
        // ...
    }
}

Comparer les champs x et y.

try {
    Point that = (Point) o;
    return this.x == that.x && this.y == that.y;
}

Gérer ClassCastException.

@Override
public boolean equals(Object o) {
    try {
        Point that = (Point) o;
        return this.x == that.x && this.y == that.y;
    } catch (ClassCastException e) {
        return false;
    }
}
Point p1 = new Point(3, 4);
Point p2 = new Point(3, 4);
System.out.println(p1.equals(p2)); // true
System.out.println(p1.equals("abc")); // false