Tag: How use hashCode and equals method in Java?

Overriding only equals() method without overriding hashCode() causes the two equal instances to have unequal hash codes , which violates the hashCode contract (mentioned in Javadoc) that clearly says, if two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two …

If two Objects are equal, according to the equals(Object) method, then hashCode() method must produce the same Integer on each of the two Objects.

The Team class overrides only equals(), but it still implicitly uses the default implementation of hashCode() as defined in the Object class. And this returns a different hashCode() for every instance of the class.3 Mar 2022

Overriding hashCode method in Java