21. Which class does all the Enums extend?
    

1. 1. Object

   
   
   

   2. Enum

   
   
   

   3. Enums

   
   
   

   4. EnumClass

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   All enums implicitly extend java.lang.Enum. Since Java does not support multiple inheritance, an enum cannot extend anything else.

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22. Are enums are type-safe?
    

1. 1. 0

   
   
   

   2. 1

   
   
   

   3. True
      

   
   
   

   4. False

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   Enums are type-safe as they have own name-space.

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23. Which of the following is the advantage of BigDecimal over double?
    

1. 1. Precision

   
   
   

   2. Garbage creation

   
   
   

   3. Memory usage

   
   
   

   4. Syntax

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   BigDecimal has unnatural syntax, needs more memory and creates great amount of garbage. But it has high precision which is useful for some calculations like money.

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24. Which of the below data type doesn’t support overloaded methods for +,-,* and /?
    

1. 1. BigDecimal

   
   
   

   2. double

   
   
   

   3. float

   
   
   

   4. int

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   int, float, double provide overloaded methods for +,-,* and /. BigDecimal does not provide these overloaded methods.

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25. What is the output of below code snippet?
    

    
       double d = 0.02;
       double e = 0.03;
       double f = e - d;
       System.out.println(c);
     
       BigDecimal _d = new BigDecimal("0.02");
       BigDecimal _e = new BigDecimal("0.03");
       BigDecimal _f = b.subtract(_d);
       System.out.println(_f);
    

1. 1. 0.01
      0.009999999999999998

   
   
   

   2. 0.01
      0.01

   
   
   

   3. 0.009999999999999998
      0.009999999999999998

   
   
   

   4. 0.009999999999999998
      0.01

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   BigDecimal provides more precision as compared to double. Double is faster in terms of performance as compared to BigDecimal.

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