Testing whether IdentityMap relies on hashCode somehow

IdentityTest.java

package jeffque;

import java.util.IdentityHashMap;
import java.util.Objects;

public class IdentityTest {

    static class SomeValue {
        int x;

        SomeValue(int x) {
            this.x = x;
        }

        @Override
        public int hashCode() {
            return Objects.hashCode(x);
        }

        @Override
        public boolean equals(Object obj) {
            if (obj instanceof SomeValue other) {
                return this.x == other.x;
            }
            return false;
        }
    }

    public static void main(String[] args) {
        final var idMap = new IdentityHashMap<SomeValue, String>();
        final var k = new SomeValue(1);
        idMap.put(k, "first");

        k.x = 42;

        System.out.println(idMap.get(k));
    }
}