Picture of Main Memory

When a program starts running there are no objects, just class definitions and a static main() method. Usually main() then constructs some objects and calls their methods to do the work of the program. In our example, main() constructed just one object and then called its calculateMPG() method.

The picture shows the variable car in the static main() method referring to the object that has been constructed following the plan given in the class definition of Car.

The static main() method is actually part of the MilesPerGallon class, which is not shown in the picture.