Iterating through a HashMap to find a key object that matches an outside object in Java

Question

I am quite new to coding in general and this may be a simple answer. I certainly hope that it is. I am trying to iterate through a HashMap and compare the Key to an outside object of the same type. When I run the method, it is not showing me that the objects match even though their values are the same. The Point class is made up from 2 integers, an x and a y. Here is my code:

for (HashMap.Entry<Point, Character> entry : map.entrySet()) {
    Point point = new Point(0,0);
    point = entry.getKey();
    if(point == outsidePoint){
       //insert code here
    }

I know that at some time during the iteration that the point object is equal to the outsidePoint object, but it will not run the code inside the if statement.

Any help would be incredibly beneficial.

`==` is for reference equality. Use `equals()` to compare separate but equivalent objects. — shmosel, Oct 13 '21 at 20:08
You need to use `.equals`, not `==`, or -- even better -- you should just do the map lookup, just using `map.get(point)`. — Louis Wasserman, Oct 13 '21 at 20:12

score 0 · Accepted Answer · answered Oct 13 '21 at 20:27

As mentioned in comments, when you want to compare two different objects of the same type in java, you have to use .equals() instead of ==. So whole code is:

for (HashMap.Entry<Point, Character> entry : map.entrySet()) {
Point point = entry.getKey();
if(point.equals(outsidePoint)){
   //insert code here
}

You can also assign entry.getKey() to point directly, there is no need for new Point().

Iterating through a HashMap to find a key object that matches an outside object in Java

1 Answers1