46. What is the output of this program?
    

    public class Result 
        {
            public static void main(String args[])
            {
                Double num = new Double(260.1);  
                boolean     p = num.isNaN();
                System.out.print(p);
            }
        }
    

1. 1. 260.1

   
   
   

   2. 260

   
   
   

   3. true

   
   
   

   4. false

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   num.isNaN() method returns returns true if i is not a number and false when i is a number. Here false is returned because i is a number i:e 260.1.

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47. Which of these exceptions is thrown by compareTo() method defined in a double wrapper?

1. 1. CastException

   
   
   

   2. ClassCastException

   
   
   

   3. SystemException

   
   
   

   4. IOException

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   compareTo() methods compare the specified object to be double, if it is not then ClassCastException is thrown.

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48. Which of these method of Double wrapper can be used to check whether a given value is infinite or not?

1. 1. checkInfinite()

   
   
   

   2. Infinite()

   
   
   

   3. checkNmber()

   
   
   

   4. isInfinite()

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   isInfinite() methods returns true if the specified value is an infinite value otherwise it returns false.

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49. Which of these methods calls update() method?

1. 1. updateObserver()

   
   
   

   2. notifyObserver()

   
   
   

   3. observeObject()

   
   
   

   4. notify()

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   notifyObserver() notifies all the observers of the invoking object that it has changed by calling update(). A null is passed as the second argument to update().

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50. Which of the following methods return the value as a double?

1. 1. getDoubleValue()

   
   
   

   2. getDouble()

   
   
   

   3. converDouble()

   
   
   

   4. doubleValue()

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   doubleValue()

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