250+ TOP MCQs on Character Extraction and Answers

Java MCQs on character extraction of Java Programming Language.

1. Which of these method of class String is used to extract more than one character at a time a String object?
a) getchars()
b) GetChars()
c) Getchars()
d) getChars()

Answer: d
Clarification: None.

2. Which of these methods is an alternative to getChars() that stores the characters in an array of bytes?
a) getBytes()
b) GetByte()
c) giveByte()
d) Give Bytes()

Answer: a
Clarification: getBytes() stores the character in an array of bytes. It uses default character to byte conversions provided by the platform.

3. In the following Java code, what can directly access and change the value of the variable name?

```
 package test;
```
```
 class Target 
```
```
 {
```
```
  public String name = "hello";
```
```
 }
```

a) any class
b) only the Target class
c) any class in the test package
d) any class that extends Target

Answer: c
Clarification: Any class in the test package can access and change name.

4. What will be the output of the following Java code?

```
public class Boxer1 
```
```
{
```
```
    Integer i;
```
```
    int x;
```
```
   public Boxer1(int y) 
```
```
   {
```
```
        x = i+y;
```
```
        System.out.println(x);
```
```
   }
```

   public static void main(String[] args)

```
   {
```
```
       new Boxer1 (new Integer(4));
```
```
   }
```
```
}
```

a) The value “4” is printed at the command line
b) Compilation fails because of an error in line
c) A NullPointerException occurs at runtime
d) An IllegalStateException occurs at runtime

Answer: d
Clarification: Because we are performing operation on reference variable which is null.

5. Which of these methods can be used to convert all characters in a String into a character array?
a) charAt()
b) both getChars() & charAt()
c) both toCharArray() & getChars()
d) all of the mentioned

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Answer: c
Clarification: charAt() return one character only not array of character.

6. What will be the output of the following Java code?

```
    class output 
```
```
    {
```

        public static void main(String args[])

```
        { 
```

           String c = "Hello i love java";

```
           int start = 2;
```
```
           int end = 9;
```

           char s[]=new char[end-start];

```
           c.getChars(start,end,s,0);
```
```
           System.out.println(s);
```
```
        }
```
```
    }
```

a) Hello, i love java
b) i love ja
c) lo i lo
d) llo i l

Answer: d
Clarification: getChars(start,end,s,0) returns an array from the string c, starting index of array is pointed by start and ending index is pointed by end. s is the target character array where the new string of letters is going to be stored and the new string will be stored from 0th position in s.
Output:

$ javac output.java
$ java output
llo i l

7. What will be the output of the following Java code?

```
    class output 
```
```
    {
```

        public static void main(String args[])

```
        {
```

            String a = "hello i love java";

            System.out.println(a.indexOf('i')+" "+a.indexOf('o') +" "+a.lastIndexOf('i')+" "+a.lastIndexOf('o'));

```
        }
```
```
    }
```

a) 6 4 6 9
b) 5 4 5 9
c) 7 8 8 9
d) 4 3 6 9

Answer: a
Clarification: indexof(‘c’) and lastIndexof(‘c’) are pre 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

8. What will be the output of the following Java code?

```
    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 is a lower case Letter
      is White space character

    b is a lower case Letter
      is White space character

    a is a lower case Letter
    A is an upper case Letter

    a is a lower case Letter
    0 is a digit

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Answer: c
Clarification: 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.
Output:

$ javac output.java
$ java output
a is a lower case Letter
A is an Upper Case Letter

9. What will be the output of the following Java code?

```
    class output 
```
```
    {
```

        public static void main(String args[])

```
        {
```
```
            char ch;
```
```
            ch = "hello".charAt(1);
```
```
            System.out.println(ch);
```
```
        }
```
```
   }
```

a) h
b) e
c) l
d) o

Answer: b
Clarification: “hello” is a String literal, method charAt() returns the character specified at the index position. Character at index position 1 is e of hello, hence ch contains e.
output:

$ javac output.java
$ java output 
e

250+ TOP MCQs on Character Extraction and Answers

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