Add more about Interfaces

Author: Hardvan

14_Abstract_Class_and_Methods/src/Abstract.java

@@ -13,6 +13,8 @@
 // Abstract Class
 abstractclassParent{
 
+inta = 100; // You can create properties in abstract class
+
 publicParent(){
 System.out.println("I am a constructor of Parent class");
  }
@@ -45,12 +47,13 @@ public void th(){
 publicclassAbstract{
 publicstaticvoidmain(String[] args){
 
-Parentp = newParent(); // Error because Parent is abstract class
+// Parent p = new Parent(); // Error because Parent is abstract class
 
 Childc = newChild();
 c.greet(); // Good Morning
+System.out.println(c.a);
 
-Child2c2 = newChild2(); // Error because Child2 is abstract class
+// Child2 c2 = new Child2(); // Error because Child2 is abstract class
 
  }
 }

15_Interfaces/1_Intro/src/Interfaces.java

@@ -1,20 +1,26 @@
 // ? Interface
-// * In English, point where two systems meet and interact.
-// * In Java, group of related methods with empty bodies.
+// * Group of related methods with empty bodies.
 
 // ? Abstract class vs Interface
-// * We can't extend multiple abstract classes
-// * But we can implement multiple interfaces.
+// * We can't EXTEND multiple abstract classes
+// * But we can IMPLEMENT multiple interfaces.
 
-// ? Interface
+// Interface
 interfaceBicycle{
+
+inta = 10; // You can create properties in interface, but not modify them (final)
+
 voidapplyBrake(intdecrement);
 
 voidspeedUp(intincrement);
 }
 
-// ? implements keyword
-classHeroimplementsBicycle{
+interfaceHorn{
+voidblowHorn();
+}
+
+// implements keyword
+classHeroimplementsBicycle, Horn{
 
 intspeed = 0; // Initial speed
 
@@ -28,7 +34,12 @@ public void speedUp(int increment){
 speed += increment;
  }
 
-voidprintStates(){
+@Override
+publicvoidblowHorn(){
+System.out.println("Pee Pee Poo Poo Dhaichuu!");
+ }
+
+voidprintSpeed(){
 System.out.println("Speed: " + speed);
  }
 }
@@ -37,9 +48,14 @@ public class Interfaces{
 publicstaticvoidmain(String[] args){
 
 Heroh = newHero();
+
+System.out.println("a: " + h.a);
+// h.a = 100; // Error because a is final
+
 h.speedUp(10);
 h.applyBrake(5);
-h.printStates(); // Speed: 5
+h.printSpeed();
+h.blowHorn();
 
  }
 }