Questions and answers for exam Preparation

MCQs

Total Questions : 51 | Page 3 of 6 pages

What is the output of this program?

import java.io.*;
public class filesinputoutput {
public static void main(String[] args) {
String obj = "abc";
byte b[] = obj.getBytes();
ByteArrayInputStream obj1 = new ByteArrayInputStream(b);
for (int i = 0; i < 2; ++ i) {
int c;
while((c = obj1.read()) != -1) {
if(i == 0) {
System.out.print(Character.toUpperCase((char)c));
obj2.write(1);
}
}
System.out.print(obj2);
}
}
}

AaBaCa
ABCaaa
AaaBaaCaa
AaBaaCaaa

Discuss Question

Answer: Option D. -> AaBaaCaaa

None.
Output:
$ javac filesinputoutput.java
$ java filesinputoutput
AaBaaCaaa

Question 22.

What is the output of this program?

class output {
public static void main(String args[])
{
StringBuffer c = new StringBuffer("Hello");
StringBuffer c1 = new StringBuffer(" World");
c.append(c1);
System.out.println(c);
}
}

Hello
World
Helloworld
Hello World

Discuss Question

Answer: Option D. -> Hello World

append() method of class StringBuffer is used to concatenate the string representation

to the end of invoking string.
Output:
$ javac output.java
$ java output
Hello World

Question 23.

What is the output of this program?

class output {
public static void main(String args[])
{
String a="hello i love java";
System.out.println(indexof('i')+" "+indexof('o')+" "+lastIndexof('i')+" "+lastIndexof('o') ));
}
}

6 4 6 9
5 4 5 9
7 8 8 9
4 3 6 9

Discuss Question

Answer: Option A. -> 6 4 6 9

indexof('c')and lastIndexof('c')are defined function which are used to get the index

of first and last occurrence of
the character pointed by c in the given array.
Output:
$ javac output.java
$ java output
6 4 6 9

Question 24.

What is the output of this program?

import java.io.*;
class Chararrayinput {
public static void main(String[] args) {
String obj = "abcdef";
int length = obj.length();
char c[] = new char[length];
obj.getChars(0,length,c,0);
CharArrayReader input1 = new CharArrayReader(c);
CharArrayReader input2 = new CharArrayReader(c, 0, 3);
int i;
try {
while ((i = input1.read()) != -1) {
System.out.print((char)i);
}
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

abc
abcd
abcde
abcdef

Discuss Question

Answer: Option D. -> abcdef

Question 25.

What is the output of this program?

import java.io.*;
class filesinputoutput {
public static void main(String args[]) {
InputStream obj = new FileInputStream("inputoutput.java");
System.out.print(obj.available());
}
}

Note: inputoutput.java is stored in the disk.

true
false
prints number of bytes in file
prints number of characters in the file

Discuss Question

Answer: Option C. -> prints number of bytes in file

obj.available() returns the number of bytes.
Output:
$ javac filesinputoutput.java
$ java filesinputoutput
1422
(Output will be different in your case)

Question 26.

What is the output of this program if input given is "Hello stop World"?

class Input_Output {
public static void main(String args[]) throws IOException {
string str;
BufferedReader obj = new BufferedReader(new InputStreamReader(System.in));
do {
str = (char) obj.readLine();
System.out.print(str);
} while(!str.equals("strong"));
}
}

Hello
Hello stop
World
Hello stop World

Discuss Question

Answer: Option D. -> Hello stop World

"stop" will be able to terminate the do-while loop only when it occurs singly in a line.

"Hello stop World" does not terminate the loop.
Output:
$ javac Input_Output.java
$ java Input_Output
Hello stop World

Question 27.

Which of the following statement is correct?

reverse() method reverses all characters.
reverseall() method reverses all characters.
replace() method replaces first occurrence of a character in invoking string with another character.
replace() method replaces last occurrence of a character in invoking string with another character.

Discuss Question

Answer: Option A. -> reverse() method reverses all characters.

reverse() method reverses all characters. It returns the reversed object on which

it was called.

Question 28.

What is the output of this program?

import java.io.*;
class filesinputoutput {
public static void main(String args[]) {
InputStream obj = new FileInputStream("inputoutput.java");
System.out.print(obj.available());
}
}

Note: inputoutput.java is stored in the disk.