Answer by Federico klez Culloca for Need to understand map.get() method after Overriding hashCode and equals in Java

HashMap's getchecks for equality with == before using equals.

So the fact that you're using the same object you used as a key (rather than an object with the same content but a different reference) makes get work.

If you try this way

public static void main(String[] args) {    Map<Student,String> map=new HashMap<>();    Student ob1=new Student("A");    Student ob2=new Student("B");    Student keyTest = new Student("A");    map.put(ob1,"A");    map.put(ob2,"B");    System.out.println(map.get(keyTest)); //different key here}

it prints null.