inheritance in depth example

src/com/in28minutes/java/oops/interfaces/InterfaceExamples.java

@@ -1,24 +1,78 @@
-package com.in28minutes.java.oops.interfaces;
-
-interface Flyable {
-	void fly();
-}
-
-class Aeroplane implements Flyable {
-	public void fly() {
-		System.out.println("Aeroplane is flying");
-	}
-}
-
-class Bird implements Flyable {
-	public void fly() {
-		System.out.println("Bird is flying");
-	}
-}
-
-public class InterfaceExamples {
-	public static void main(String[] args) {
-		Flyable flyable = new Bird();
-		flyable.fly();
-	}
-}
+// base class 
+class Bicycle  
+{ 
+    // the Bicycle class has two fields 
+    public int gear; 
+    public int speed; 
+
+    // the Bicycle class has one constructor 
+    public Bicycle(int gear, int speed) 
+    { 
+        this.gear = gear; 
+        this.speed = speed; 
+    } 
+
+    // the Bicycle class has three methods 
+    public void applyBrake(int decrement) 
+    { 
+        speed -= decrement; 
+    } 
+
+    public void speedUp(int increment) 
+    { 
+        speed += increment; 
+    } 
+
+    // toString() method to print info of Bicycle 
+    public String toString()  
+    { 
+        return("No of gears are "+gear 
+                +"\n"
+                + "speed of bicycle is "+speed); 
+    }  
+} 
+
+// derived class 
+class MountainBike extends Bicycle  
+{ 
+
+    // the MountainBike subclass adds one more field 
+    public int seatHeight; 
+
+    // the MountainBike subclass has one constructor 
+    public MountainBike(int gear,int speed, 
+                        int startHeight) 
+    { 
+        // invoking base-class(Bicycle) constructor 
+        super(gear, speed); 
+        seatHeight = startHeight; 
+    }  
+
+    // the MountainBike subclass adds one more method 
+    public void setHeight(int newValue) 
+    { 
+        seatHeight = newValue; 
+    }  
+
+    // overriding toString() method 
+    // of Bicycle to print more info 
+    @Override
+    public String toString() 
+    { 
+        return (super.toString()+ 
+                "\nseat height is "+seatHeight); 
+    } 
+
+} 
+
+// driver class 
+public class Test  
+{ 
+    public static void main(String args[])  
+    { 
+
+        MountainBike mb = new MountainBike(3, 100, 25); 
+        System.out.println(mb.toString()); 
+
+    } 
+}