Create a program Using Constructors?

The further program uses the constructor to initialize a car rather than setting the areas directly.
class CarTest7 {

public static void main(String args[]) {

Car c = new Car("New York A45 636", 123.45);

System.out.println(c.getLicensePlate() + " is moving at " + c.getSpeed() +
" kilometers per hour.");

for (int i = 0; i < 15; i++) {
c.accelerate(10.0);
System.out.println(c.getLicensePlate() + " is moving at " + c.getSpeed()
+ " kilometers per hour.");
}

}
}
You no longer required knowing about the fields licensePlate, speed and maxSpeed. All you required to know is how to construct a new car and how to print it.

You might ask whether the setLicensePlate() method is still required since it's now set in a constructor. The common answer to this question depends on the use to that the Car class is to be put. The exact question is whether a car's license plate may required to be changed after the Car object is formed.

A few classes may not change after they're created; or, if they do change, they'll represent a different object. The most general such class is String. You cannot change a string's data. You can only form a new String object. Such objects are known as immutable.