How default .equals and .hashCode will work for my classes?

Question

Say I have my own class

public class MyObj { /* ... */ }

It has some attributes and methods. It DOES NOT implement equals, DOES NOT impleme

Answer 1

If you do not provide your own implementation, one derived from Object would be used. It is OK, unless you plan to put your class instances into i.e. HashSet (any collection that actually use hashCode() ), or something that need to check object's equality (i.e. HashSet's contains() method). Otherwise it will work incorrectly, if that's what you are asking for.

It is quite easy to provide your own implementation of these methods thanks to HashCodeBuilder and EqualsBuilder from Apache Commons Lang.