Inheritance IS-A and HAS-A relation

Car.java

package inheritanceIsaAndHasA;

public class Car {
	//color and maxSpeed are instance variables
	private String color;
	private int maxSpeed;

	//Below are methods of Car class
	public void carInfo() {
		System.out.println("Car Color= " + color + " Max Speed= " + maxSpeed);
	}

	public void setColor(String color) {
		this.color = color;
	}

	public void setMaxSpeed(int maxSpeed) {
		this.maxSpeed = maxSpeed;
	}
}

Engine.java

package inheritanceIsaAndHasA;

public class Engine {
	
	public void start() {
		System.out.println("Engine Started:");
	}

	public void stop() {
		System.out.println("Engine Stopped:");
	}
}

Maruti.java

package inheritanceIsaAndHasA;

//Maruti is specific type of Car which extends Car class means Maruti IS-A Car
public class Maruti extends Car {
	// Maruti extends Car and thus inherits all methods from Car (except final and static)
	// Maruti can also define all its specific functionality
	public void MarutiStartDemo() {
		Engine MarutiEngine = new Engine();
		MarutiEngine.start();
		//Maruti class uses Engine object’s start() method via composition. We can say that Maruti class HAS-A Engine
	}
}

RelationsDemoTest.java

package inheritanceIsaAndHasA;

//RelationsDemo class is making object of Maruti class and initialized it. Though Maruti class does not have setColor(), 
//setMaxSpeed() and carInfo() methods still we can use it due to IS-A relationship of Maruti class with Car class.
public class RelationsDemoTest {
	public static void main(String[] args) {
		Maruti myMaruti = new Maruti();
		myMaruti.setColor("RED");
		myMaruti.setMaxSpeed(180);
		myMaruti.carInfo();

		myMaruti.MarutiStartDemo();
	}
}