HashMap 的 containsKey 方式未按预期运行

Today I was doing some pathfinding when I had to use contains() to find if a class Coord was in an other keySet() of Coord. I found that when I used to premade method containsKey(), it was simply not working as I wanted. I made a test to find out what is happening and here it is:

HashMap<Coord, Coord> test = new HashMap<Coord, Coord>();
test.put(new Coord(3, 3), new Coord(0, 0));

System.out.println("HashMap test for containsKey : " + test.containsKey(new Coord(3, 3)));

boolean containsKey = false;
for(Coord a : test.keySet())
{
    if(a.equals(new Coord(3, 3)))
    {
        containsKey = true;
    }
}

System.out.println("My test for containsKey : "+containsKey);

令人惊讶的是，这是我发现的:

HashMap test for containsKey : false
My test for containsKey : true

public class Coord
{
    public float x, y;

    public Coord(float a, float b)
    {
        this.x = a;
        this.y = b;
    }

    @Override
    public boolean equals(Object b)
    {
        if(b instanceof Coord)
        {
            Coord casted = (Coord) b;
            return casted.x == x && casted.y == y;
        }
        return false;
    }
}