21. Which of these keywords is used to refer to member of base class from a subclass?

1. 1. this

   
   
   

   2. upper

   
   
   

   3. super

   
   
   

   4. static

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   Whenever a subclass needs to refer to its immediate superclass, it can do so by use of the keyword super.

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22. Which of these method of String class is used to obtain character at specified index?

1. 1. charat()

   
   
   

   2. charAt()

   
   
   

   3. Charat()

   
   
   

   4. char()

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   charAt()

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23. String in Java is a?

1. 1. character array

   
   
   

   2. class

   
   
   

   3. object

   
   
   

   4. variable

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   class

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24. What will s2 contain after following lines of code?
    

    
    String str1 = "one";
    String str2 = str1.concat("two")
    

1. 1. onetwo

   
   
   

   2. twoone

   
   
   

   3. one

   
   
   

   4. two

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   Two strings can be concatenated by using concat() method.

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25. Which of these method of class StringBuffer is used to find the length of current character sequence?

1. 1. Length()

   
   
   

   2. capacity()

   
   
   

   3. Capacity()

   
   
   

   4. length()

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   length()

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