Java class with no constructor?

Question

I have this class

class Customer{
    int ID;
    Time arriveTime;
    Time serviceTime;
    Time completeTime;
    int transaction;
}

Don\'t I

Answer 1

Yes, you need a constructor to assign parameters to your class during object creation, or you could reference each variable individually though the instance and assign it, e.g:

 Customer c = new Customer();
 c.id = 0;
 // etc

A constructor just makes this easier as you do not need to write more code than necessary.

I do recommend using constructors to assign various values to a class instance instead of doing it manually every time you create an instance of an object.