A constant is a variable whose value cannot change once it has been assigned.
However, using the
final keyword with a variable that references a normal object does not guarantee the contents of that object will stay the same. It only guarantees that the variable will always hold a reference to the same object. See, Final Keyword and Objects for more information.
final keyword to declare an
int variable as a constant:
final int DAYS_IN_JANUARY = 31;