So that the Entrance class could use the Garage reference, viz, "garage" to call the
enter method in the Garage class.
class Entrance extends Thread
{
Garage garage;
public Exit(Garage garage, int threadNum)
{
this.garage = garage;
...
public void run()
{
for(int j = 0; j < 10; j++)
{
garage.enter(number, j+1);