Write Output of Java Program - Exam Sample Questions

Answers are given at end.

1 public class StringTest {
public static void main(String args[]){
String t1=new String("Text");
String t2=new String("Text");
System.out.println(t1==t2);

String t3="Text";
String t4="Text";
System.out.println(t3==t4);
  System.out.println(t1==t4);
System.out.println(t1.equals(t3));
}
}

2 public class ExceptionTest {
 public static void main(String[] args) {
     try {
System.out.println("Welcome to Java");
int[] a = new int[10];
a[10] = 1;
System.out.println("Welcome to Python");
    } catch (Exception ex) {
System.out.println("There is an exception”);
    }
    System.out.println("Bye.");
 }
}


3 class A{
    public int x = 1;

public A(int i){
x += i;
}
}

class B extends A {
public B(int i){
super(i);
x += i;
}
}

public class  Test{
public static void main(String args[]) {

    A arr[] = new A[2];
        arr[0] = new A(1);
        arr[1] = new B(2);
        System.out.println(arr[0].x + arr[1].x);
}
}


4 class A {
    public String toString() {
        return "class A";
    }
    public void method1() {
        System.out.println("method1 of class A");
    }
    public void method2() {
        System.out.println("method2 of class A");
    }
    public static void method3(){
        System.out.println("method3 of class A");
    }
}

class B extends A {
    public String toString() {
        return "class B";
    }
    public void method2() {
        System.out.println("method2 of class B");
    }
    public static void method3(){
        System.out.println("method3 of class B");
    }
}

class C extends B { }

class D extends C {
    public void method1() {
        System.out.println("method1 of class D");
    }
    public static void method3(){
        System.out.println("method3 of class B");
    }
    public String toString(){
            return "Class D";
    } 
}

public class Test {
    public static void main(String args[]){
        A[] elements = {new A(),  new B(),  new C(), new D()};

            for (A obj : elements) {
                System.out.println(obj);
                obj.method1();
                obj.method2();
                obj.method3();
            }
}
}


5 class Nest{
   public static void main(String args[]){
//Parent try block
     try{
    //Child try block1
         try{
            System.out.println("Inside block1");
            int b =45/0;
            System.out.println(b);
         } catch(ArithmeticException e1){
            System.out.println("Exception: e1");
         }

         //Child try block2
         try{
            System.out.println("Inside block2");
            int b =45/0;
            System.out.println(b);
         } catch(ArrayIndexOutOfBoundsException e2){
            System.out.println("Exception: e2");
         }
         System.out.println("Just other statement");

    } catch(ArithmeticException e3){
    System.out.println("Arithmetic Exception");
        System.out.println("Inside parent try catch block");

    } catch(ArrayIndexOutOfBoundsException e4){
    System.out.println("ArrayIndexOutOfBoundsException");
       System.out.println("Inside parent try catch block");

    } catch(Exception e5){
    System.out.println("Exception");
       System.out.println("Inside parent try catch block");
    }
     System.out.println("Next statement..");
  }
}


6 class X {
int product;
public X(int x, int y) {
product = x * y;
}
void multiplication() {
  System.out.println("Multiplication of x and y is: " + product);
}
}

class Y extends X {

int productAll;
public Y(int x, int y, int z) {
super(x, y);
productAll = x * y * z;
}

void multiplication() {
  super.multiplication();
  System.out.println("Multiplication of  x, y and z is: " + productAll);
}
}

// Class with main entry point
public class Question {
public static void main(String args[]) {
Y y = new Y(2,3,4);
y.multiplication();
}
}


7 public enum Gender {
    MALE, FEMALE;

    public static void main(String[] args) {
        Gender gender = Gender.MALE;
        Gender[] genders = Gender.values();     
        if (gender == genders[1]) System.out.print("A-");
        if (gender == Gender.MALE && Gender.FEMALE != null)
            System.out.print("B-");

        if (genders.length > 1)
            System.out.print(Gender.MALE + "-" + (genders[1]));
    }
}


8 public class Box {
    public Box() {
        System.out.print("D");
    }
    public Box(int n){
        this();
        System.out.print("T");
        System.out.print(m1());
    }
    String m1(){
        System.out.print("N");
        return "S";
    }
    public static void main(String[] args) {
        Box b = new Box(8);
        b.m1();
    }
}

9.
public enum E1 {
    ONE, TWO;
    public static void main(String[] args) {
        E1 e1 = E1.ONE;
        E1[] arr = E1.values();
        if (e1 == arr[1]) {
            System.out.print("X");
        }
        if (e1 == E1.ONE && E1.TWO != null)
            System.out.print("W");
        if(arr.length > 1)
            System.out.print(E1.ONE + "-" + (arr[1]));
    }
}

10.
public class Arr {
    static int[] n = {1,2,3};

    static void m1(int n){
        Arr.n[0]++;
        n++;
    }
    static void m2(int[] m){
        m[0]++;
    }
    public static void main(String[] args) {
        int n[] = {4,5,6};
        m1(n[0]);
        System.out.println(n[0]);
        n = Arr.n;
        m2(n);
        System.out.println(n[0]);
     }
}

11.
public class Arr2 {
    public static void main(String[] args) {
        int[][] nums = new int[2][];
        nums[0] = new int[]{1, 2};
        nums[1] = new int[]{3, 4, 5};
        for(int i=0; i<nums.length; i++)
            for(int j=0; j<nums[0].length;j++){
                System.out.print(nums[j][i] + "-");
            }
    }
}

12.
public class Student {
    static int n = 0;
    public Student() {
        n++;
    }
    void m1(int n) {
        n = Student.n - 1;
    }
    public static void main(String[] args) {
        for (int i = 1; i <= 3; i++) {
            new Student().m1(Student.n);
        }
        System.out.println(Student.n);
    }
}

13.
public class Box {
    public Box() {
        System.out.print( m1() + "T" );
    }

    public Box(int n){
        m1();
    }
    String m1(){
        System.out.print("N");
        return "S";
    }
    public static void main(String[] args) {
        Box b = new Box(1);
        b.m1();
        b = new Box();
    }

Solution:

1. 

false

true

true

2.

Welcome to Java

There is an exception

Bye.

3.

7

4. 

class A

method1 of class A

method2 of class A

method3 of class A

class B

method1 of class A

method2 of class B

method3 of class A

class B

method1 of class A

method2 of class B

method3 of class A

Class D

method1 of class D

method2 of class B

method3 of class A

5.

Inside block1

Exception: e1

Inside block2

Arithmetic Exception

Inside parent try catch block

Next statement..

6. 

Multiplication of x and y is: 6

Multiplication of  x, y and z is: 24

7.

B-MALE-FEMALE

8.

DTNSN

9.
WONE-TWO

10.
43

11.
1-3-2-4-

12.
3

13.
NNNST