1. What does an interface contain?

1. 1. Method declaration

   
   
   

   2. Method name

   
   
   

   3. Method definition

   
   
   

   4. Method declaration and definition

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   Interface contains the only declaration of the method.

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2. Which of the following is the correct way of implementing an interface N by class M?

1. 1. class M imports N{}

   
   
   

   2. class M extends N{}

   
   
   

   3. class M implements N{}

   
   
   

   4. All of above

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   Concrete class implements an interface. They can be instantiated.

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3. All methods must be implemented of an interface.

1. 1. False

   
   
   

   2. True

   
   
   

   3. NA

   
   
   

   4. NA

   
   
   

   5. NA

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   Concrete classes must implement all methods in an interface. Through interface multiple inheritance is possible.

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4. What type of variable can be defined in an interface?

1. 1. public final

   
   
   

   2. public static

   
   
   

   3. static final

   
   
   

   4. private final

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   variable defined in an interface is implicitly final and static. They are usually written in capital letters.

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5. What will happen if we provide concrete implementation of method in interface?

1. 1. Compilation failure

   
   
   

   2. The concrete class implementing that method need not provide implementation of that method

   
   
   

   3. Method not found exception is thrown

   
   
   

   4. Runtime exception is thrown

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   The methods of interfaces are always abstract. They provide only method definition.

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