The equals and hashcode methods are extremely important to be mastered because of the lack of knowledge of them may cause catastrophic bugs. Learn how to add unique elements into the Set interface by taking this Java Challenge and take your Java skills to a whole new level! By bonus get the Java certification with this knowledge! For more, go to nobugsproject.com And, as promised, this is the link with the deep explanation about equals and hashcode:

https://www.javaworld.com/article/330…

Get the code of the Java Challengers and run your own tests:

https://javachallengers.com/code