public class Car {

String name;
int price;
Engine eng;   //---> Cant understand this logic

public int inceasePrice(int increment){
price = price + increment;
return price;
}

public Engine getEngine(){
return eng;
}

}

*************************************************

public class TestCar {

public static void main(String arg[]){

Car c1 = new Car();
c1.name="BMW";
c1.price=99999999;

c1.inceasePrice(100);
System.out.println(c1.price);

Engine e = new Engine();
e.mdNumber="AE9282";
e.milage=20;

c1.eng=e; //---> Cant understand this logic

System.out.println(c1.eng.mdNumber); //---> Cant understand this logic
System.out.println(c1.eng.milage);  //---> Cant understand this logic