HashSet with two equals object?

Question

I created an object HashSet, and the value is an object (Triple) which is my own class. But I get a strange thing, when there are two equal objects on my HashSet, is it poss

Answer 1

Looks like it returns true for Strings only...i tries to run the below code

            final HashSet carHashSet = new HashSet();
    final Car c1 = new  Car("black","ZX","deisel");
    final Car c2 = new  Car("black","ZX","deisel");
    carHashSet.add(c1);

    if (carHashSet.contains(c2))
        System.out.println("has c2 obj");
    else
        System.out.println("dont have C2 obj");

    final HashSet stringHashSet = new HashSet();

    final String k1 = "test";
    final String k2 = "test";//final String k2 = "Test";

    stringHashSet.add(k1);

    if (stringHashSet.contains(k2))
        System.out.println("has k2 obj");
    else
        System.out.println("dont have k2 obj");

the output is as below:

dont have C2 obj has k2 obj

when i change k2 to final String k2 = "Test";, the output is

dont have C2 obj dont have k2 obj