Java Language | 10 Minute‐Test 26


Instruction

  • Total number of questions : 10.
  • Time alloted : 10 minutes.
  • Each question carry 1 mark.
  • No Negative marks
  • DO NOT refresh the page.
  • All the best :-).

1.

What is the output of this program?

class String_demo {

        public static void main(String args[])

        {

            int ascii[] = { 65, 66, 67, 68};

            String s = new String(ascii, 1, 3);

            System.out.println(s);

        }

   }

A.
ABC
B.
BCD
C.
CDA
D.
ABCD

Your Answer: Option (Not Answered)

Correct Answer: Option B

Explanation:

ascii is an array of integers which contains ascii codes of Characters A, B, C, D. String(ascii, 1, 3) is an constructor which initializes s with Characters corresponding to ascii codes stored in array ascii, starting position being given by 1 & ending position by 3, Thus s stores BCD.

2.

What is the output of this program?

    class output {

        public static void main(String args[])

        {

            char c[]={'a', '1', 'b' ,' ' ,'A' , '0'};

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

            {

                   if(Character.isDigit(c[i]))

                       System.out.println(c[i]+" is a digit");

                   if(Character.isWhitespace(c[i]))

                       System.out.println(c[i]+" is a Whitespace character");

                   if(Character.isUpperCase(c[i]))

                       System.out.println(c[i]+" is an Upper case Letter");

                   if(Character.isLowerCase(c[i]))

                       System.out.println(c[i]+" is a lower case Letter");

               i=i+3;

            }

        }

    }

A.
a is a lower case Letter
is White space character
B.
b is a lower case Letter
is White space character
C.
a is a lower case Letter
A is a upper case Letter
D.
a is a lower case Letter
0 is a digit

Your Answer: Option (Not Answered)

Correct Answer: Option C

Explanation:

Character.isDigit(c[i]),Character.isUpperCase(c[i]),Character.isWhitespace(c[i]) are the function of library java.lang. They are used to find weather the given character is of specified type or not. They return true or false i:e Boolean variable.

3.

What is the output of this program?

    class output {

        public static void main(String args[])

        {

           String s1 = "Hello";

           String s2 = s1.replace('l','w');

           System.out.println(s2);

        }

    }

A.
hello
B.
helwo
C.
hewlo
D.
hewwo

Your Answer: Option (Not Answered)

Correct Answer: Option D

Explanation:

replace() method replaces all occurrences of one character in invoking string with another character. s1.replace(‘l’,’w’) replaces every occurrence of ‘l’ in hello by ‘w’, giving hewwo.

4.

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);

        }

    }

A.
Hello
B.
World
C.
Helloworld
D.
Hello World

Your Answer: Option (Not Answered)

Correct Answer: Option D

Explanation:

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

5.

What is the output of this program?

    class output {

        public static void main(String args[])

        {

           StringBuffer s1 = new StringBuffer("Hello");

           s1.setCharAt(1,'x');

           System.out.println(s1);

        }

    }

A.
xello
B.
xxxxx
C.
Hxllo
D.
Hexlo

Your Answer: Option (Not Answered)

Correct Answer: Option C

Explanation:

None.

6.

What is the output of this program?

    class output {

        public static void main(String args[])

        {

           String s1 = "Hello";

           String s2 = new String(s1);

           String s3 = "HELLO";

           System.out.println(s1.equals(s2) + " " + s2.equals(s3));

        }

    }

A.
true true
B.
false false
C.
true false
D.
false true

Your Answer: Option (Not Answered)

Correct Answer: Option C

Explanation:

None.

7.

What is the output of this program?

    package pkg;

    class display {

        int x;

        void show() {

            if (x > 1)

                System.out.print(x + " ");

        }

    }

    class packages {

        public static void main(String args[]) {

            display[] arr=new display[3];

            for(int i=0;i<3;i++)

                arr[i]=new display();

            arr[0].x = 0;     

            arr[1].x = 1;

            arr[2].x = 2;

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

                arr[i].show();

         }

    }

Note : packages.class file is in directory pkg;

A.
0
B.
1
C.
2
D.
0 1 2

Your Answer: Option (Not Answered)

Correct Answer: Option C

Explanation:

None.

8.

What is the output of this program?

    interface calculate {

        void cal(int item);

    }

    class display implements calculate {

        int x;

        public void cal(int item) {

            x = item * item;           

        }

    }

    class interfaces {

        public static void main(String args[]) {

            display arr = new display;

            arr.x = 0;     

            arr.cal(2);

            System.out.print(arr.x);

        }

    }

A.
0
B.
2
C.
4
D.
None of the mentioned

Your Answer: Option (Not Answered)

Correct Answer: Option C

Explanation:

None.

9.

What is the output of this program?

    class isinfinite_output {

        public static void main(String args[]) {

            Double d = new Double(1 / 0.); 

            boolean x = d.isInfinite();

            System.out.print(x);

        }

    }

A.
0
B.
1
C.
true
D.
false

Your Answer: Option (Not Answered)

Correct Answer: Option C

Explanation:

isInfinite() method returns true is the value being tested is infinitely large or small in magnitude. 1/0. is infinitely large in magnitude hence true is stored in x.

10.

What is the output of this program?

    class Output {

        public static void main(String args[]) {

            Integer i = new Integer(257); 

            byte x = i.byteValue();

            System.out.print(x);

        }

    }

A.
0
B.
1
C.
256
D.
257

Your Answer: Option (Not Answered)

Correct Answer: Option B

Explanation:

i.byteValue() method returns the value of wrapper i as a byte value. i is 257, range of byte is 256 therefore i value exceeds byte range by 1 hence 1 is returned and stored in x.


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