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

Not necessarily, as by default your attributes (values) without a visibility modifier can be set directly on instances of Customer from code in the same package.

For example:

Customer c = new Customer(); // default constructor 
c.ID = 5;
... (etc.)

More on modifier access levels here.