2. Steps to override equals()
● Do this check -- if yes then return true.
● Do null check -- if yes then return false.
● Do the instanceof check, if instanceof return false than return false from equals
in Java ,we can use getClass() method for type identification because instanceof
check returns true for subclass also.
if((obj == null) || (obj.getClass() != this.getClass()))
return false;
● Type cast the object; note the sequence instanceof check must be prior to
casting object.
● Compare individual attribute starting with numeric attribute because comparing
numeric attribute is fast and use short circuit operator for combining checks.
5. Overriding hashCode()
● Both equal() and hashCode() belong to Object
class.
● It is not always necessary to override hashcode
and equals.
● But if you think you need to override one, then
you need to override both of them.
● We must overload hashCode() when equals() is
overrided because to access the collection class
effectively without violating the rules.
