How do I compare objects in Java?

How do I compare objects in Java?

In Java, you can compare objects using the equals() method or the compareTo() method if the class implements the Comparable interface.

What is the difference between == and equals()?

The == operator checks for reference equality, meaning it checks if both references point to the same object. The equals() method checks for value equality, meaning it checks if the objects are logically equivalent.

Can you give me an example of using compareTo()?

Sure! If you have a class Person that implements Comparable, you can compare two Person objects based on their age like this: public int compareTo(Person other) { return this.age - other.age; }.

What happens if I don't override equals() and hashCode()?

If you don't override equals() and hashCode(), the default implementations from the Object class will be used, which may lead to incorrect behavior when using collections like HashMap.