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

The fields can be set from outside the class, meaning you can use another class to set the values.

A constructor however is a more convenient way to do this indeed and can shield manipulations to the fields by another class (implemented by some programmer who might disturb the intended functionality).

In case a class only is implemented to store a record, you can make the fields private and final and implement the appropriate getters.