66. Which of these method is used add an element and corresponding key to a map?

1. 1. redo()

   
   
   

   2. add()

   
   
   

   3. set()

   
   
   

   4. put()

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   Maps revolve around two basic operations – get() and put(). to put a value into a map, use put(), specifying the key and the value. To obtain a value, call get() , passing the key as an argument. The value is returned.

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67. Which of these methods can be used to obtain set of all keys in a map?

1. 1. keyall()

   
   
   

   2. keySet()

   
   
   

   3. getAll()

   
   
   

   4. getKeys()

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   keySet() methods is used to get a set containing all the keys used in a map. This method provides set view of the keys in the invoking map.

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68. Which of these method Map class is used to obtain an element in the map having specified key?

1. 1. look()

   
   
   

   2. search()

   
   
   

   3. get()

   
   
   

   4. set()

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   get()

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69. Which of these method is used to remove all keys/values pair from the invoking map?

1. 1. removeAll()

   
   
   

   2. clear()

   
   
   

   3. remove()

   
   
   

   4. delete()

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   remove()

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70. Which of these classes provide implementation of map interface?

1. 1. DynamicList

   
   
   

   2. ArrayList

   
   
   

   3. LinkedList

   
   
   

   4. HashMap

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   AbstractMap, WeakHashMap, HashMap and TreeMap provide implementation of map interface.

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