pidoras

//Test.java
import java.util.HashMap;

public class Test {

    public static void main(String[] args) {
        HashMap<TestClass, Integer> hashMap = new HashMap<>();
        hashMap.put(new TestClass(), 1);
    }
}

//TestClass.java

class TestClass {

    @Override
    public int hashCode()
    {
        System.out.println("Inside hashCode of TestClass");
        return 1;
    }
}