Sun Certified Java Programmer (SCJP) MCQ

Find the given file.

package com.concretepage;

public class A extends B {

public static void main(String[] args) {

Short myNum = 7;

System.out.println(add(myNum, 6));

}

}

class B {

int add(int x, int y) { return x + y; }

}

What is the result?

What is the output for the below code?

public class A {

int add(int i, int j){

return i+j;

}

}

public class B extends A{

public static void main(String argv[]){

short s = 9;

System.out.println(add(s,6));

}

}

class A {

A(String s) {

}

A() {

}

}

1. class B extends A {

2. B() { }

3. B(String s) {

4. super(s);

5. }

6. void test() {

7. // insert code here

8. }

9. }

Which of the below code can be insert at line 7 to make clean

compilation?

What is the output for the below code ?

public class A {

int k;

boolean istrue;

static int p;

public void printValue() {

System.out.print(k);

System.out.print(istrue);

System.out.print(p);

}

}

public class Test{

public static void main(String argv[]){

A a = new A();

a.printValue();

}

}

Find the given file.

package com.concretepage;

public class Computer implements Device{

public void doIt() { }

}

abstract class Phone1 extends Computer { }

abstract class Phone2 extends Computer{

public void doIt(int x) { }

}

class Phone3 extends Computer implements Device{

public void doStuff() { }

}

interface Device {

public void doIt();

}

What is the result?

What will be the result of compiling the following code:

public class SuperClass {

public int doIt(String str, Integer… data)throws Exception{

String signature = “(String, Integer[])”;

System.out.println(str + ” ” + signature);

return 1;

}

}

public class SubClass extends SuperClass{

public int doIt(String str, Integer… data)

{

String signature = “(String, Integer[])”;

System.out.println(“Overridden: ” + str + ” ” +

signature);

return 0;

}

public static void main(String… args)

{

SuperClass sb = new SubClass();

sb.doIt(“hello”, 3);

}

}

What is the output for the below code?

public class Test {

public static void main(String[] args){

String value = “abc”;

changeValue(value);

System.out.println(value);

}

public static void changeValue(String a){

a = “xyz”;

}

}

ou have two class files name Test.class and Test1.class inside javaproject directory.

Test.java source code is:

public class Test{

public static void main (String[] args){

System.out.println(“Hello Test”);

}

}

Test1.java source code is :

public class Test1{

public static void main (String[] args){

System.out.println(“Hello Test1″);

}

}

you have issued below commands from command prompt.

cd javaproject

java Test Test1

What is the output?

Find the given file.

package com.concretepage;

class Road {

public static void main(String[] args) {

for(int __x = 0; __x < 3; __x++) ;

int #lb = 7;

long [] x [5];

Boolean []ba[];

}

enum Traffic { RED, YELLOW, GREEN };

}

What is the result?

 What is the output for the below code?

public class A {

static{System.out.println(“static”);}

{ System.out.println(“block”);}

public A(){

System.out.println(“A”);

}

public static void main(String[] args){

A a = new A();

}

}

What is the output for the below code?

interface A {

public void printValue();

}

1. public class Test{

2. public static void main (String[] args){

3. A a1 = new A() {

4. public void printValue(){

5. System.out.println(“A”);

6. }

7. };

8. a1.printValue();

9. }

10. }

Find the given file.

package com.concretepage;

enum Day {

MON("1"), TUE("2"), WED("3");

String s;

Day(String s) { this.s = s; }

}

public class Test {

static Day d;

public static void main(String[] args) {

System.out.println(d.MON.s + " " + d.TUE.s);

}

}

What is the result?

What is the output for the below code?

public class A {

public void printName(){

System.out.println(“Value-A”);

}

}

public class B extends A{

public void printName(){

System.out.println(“Name-B”);

}

}

public class C extends A{

public void printName(){

System.out.println(“Name-C”);

}

}

1. public class Test{

2. public static void main (String[] args) {

3. B b = new B();

4. C c = new C();

5. b = c;

6. newPrint(b);

7. }

8. public static void newPrint(A a){

9. a.printName();

10. }

11. }

Choose the correct statement.

Find the given file.

package com.concretepage;

public class Test {

public enum Days { MON, TUE, WED, THU };

public static void main(String[] args) {

for(Days d : Days.values() );

Days [] d2 = Days.values();

System.out.println(d2[3]);

}

}

What is the result?

What is the output for the below code?

public class A {

int i = 10;

public void printValue() {

System.out.println(“Value-A”);

}

}

public class B extends A{

int i = 12;

public void printValue() {

System.out.print(“Value-B”);

}

}

public class Test{

public static void main(String argv[]){

A a = new B();

a.printValue();

System.out.println(a.i);

}

}

try{

File f = new File(“a.txt”);

}catch(Exception e){

}catch(IOException io){

}

Is this code create new file name a.txt?

What is the output for the below code?

1. public class Test {

2. public static void main(String[] args){

3. byte b = 6;

4. b+=8;

5. System.out.println(b);

6. b = b+7;

7. System.out.println(b);

8. }

9. }

What is the output for the below code?

public class C {

}

public class D extends C{

}

public class A {

public C getOBJ(){

System.out.println(“class A – return C”);

return new C();

}

}

public class B extends A{

public D getOBJ(){

System.out.println(“class B – return D”);

return new D();

}

}

public class Test {

public static void main(String… args) {

A a = new B();

a.getOBJ();

}

}