interface A {

}

class C {

}

class B extends D implements A {

}

public class Test {

public static void main(String[] args) {

B b = new B();

if (b instanceof A)

System.out.println("b is an instance of A");

if (b instanceof C)

System.out.println("b is an instance of C");

}

}

class D extends C {

}

class Demo{

public static void main(String[] args){

int x = div(1,2);

try{

}catch(Exception e){

System.out.println(e);

}

System.out.println(x);

}

public static int div(int a,int b){

return a / b ;

}

}

public class Test {

public static void main(String[] args) {

new Person().printPerson();

new Student().printPerson();

}

}

class Student extends Person {

@Override

public String getInfo() {

return "Student";

}

}

class Person {

public String getInfo() {

return "Person";

}

public void printPerson() {

System.out.println(getInfo());

}

}

public class Test {

public static void main(String[] args) {

new B();

}

}

class A {

int i = 7;

public A() {

System.out.println("i from A is " + i);

}

public void setI(int i) {

this.i = 2 * i;

}

}

class B extends A {

public B() {

setI(20);

}

@Override

public void setI(int i) {

this.i = 3 * i;

}

}

class A {

public A() {

System.out.println( "The default constructor of A is invoked");

}

}

class B extends A {

public B() {

System.out.println("The default constructor of B is invoked");

}

}

public class C {

public static void main(String[] args) {

B b = new B();

}

}