AD_Java Basics

Predict the output

int x = 10;

if (x = 20) {

System.out.println("True");

} else {

System.out.println("False");

}

• True

• False

• Compilation Error

• Runtime error

for (int i = 0; i < 5; i++);

{

System.out.println("Hello");

}

How many times does "Hello" print?

• 0 times

• 1 time

• 5 times

• Compilation error

Predict the output:
public class Test {

static public void main(String[] args) {

System.out.println("Executed");

}

}

• Error – Invalid main method

• Executes and prints "Executed"

• Error – Missing return type

• JVM throws exception

Predict the output:

public class Demo {

public static void main(String args) {

System.out.println("Run");

}

}

• Prints "Run"

• Compilation error

• Runs but no output

• JVM error: main method not found

Predict the output:
class A {

int x = 10;

}

class B extends A {

int x = 20;

}

public class Test {

public static void main(String[] args) {

A obj = new B();

System.out.println(obj.x);

}

}

• 10

• 20

• Compilation error

• Runtime error

Predict the output:
class Parent {

private void show() {

System.out.println("Parent");

}

}

class Child extends Parent {

void show() {

System.out.println("Child");

}

}

public class Main {

public static void main(String[] args) {

Parent p = new Child();

p.show();

}

}

• Prints "Child"

• Prints "Parent"

• Compilation error

• Runtime error

Predict the output:
int arr[] = new int[5];

System.out.println(arr[0]);

• 0

• Garbage value

• Compilation error

• Runtime error

Predict the output:
int arr[] = new int[3];

arr[0] = 10;

arr[1] = 20;

arr[2] = 30;

arr[3] = 40;

System.out.println(arr[3]);

• 0

• Compilation Error

• 40

• Runtime error

Debug if any error:
final class Base { }

class Derived extends Base { }

• Runs fine

• Compilation error

• Runtime error

• Prints nothing

________ static ________ main(String[] args)