Wrapper classes - Java (MCQ) questions and answers

Dear Readers, Welcome to Wrapper classes multiple choice questions and answers with explanation. These objective type Wrapper classes questions are very important for campus placement test and job interviews. Specially developed for the Networking freshers and professionals, these model questions are asked in the online technical test and interview of many IT companies.

1)   Which method when implemented must return true while there are still more elements to extract, and false when all the elements have been enumerated?
- Published on 19 Oct 15

a. Object nextElement( )
b. boolean hasMoreElements( )
c. Both A & B
d. None of the above
Answer  Explanation 

ANSWER: boolean hasMoreElements( )

Explanation:
No explanation is available for this question!

2)   Which defines a method called nextElement that is used to get the next element in a data structure that contains multiple elements?
- Published on 20 Jul 15

a. Bitset
b. Vector
c. Stack
d. Enumeration
Answer  Explanation 

ANSWER: Enumeration

Explanation:
No explanation is available for this question!

3)   Consider the following two statements

int x = 25;
Integer y = new Integer(33);
What is the difference between these two statements?
- Published on 17 Jul 15

a. Primitive data types
b. primitive data type and an object of a wrapper class
c. Wrapper class
d. None of the above
Answer  Explanation 

ANSWER: primitive data type and an object of a wrapper class

Explanation:
No explanation is available for this question!

4)   Which allows the caller to remove elements from the underlying collection during the iteration with well-defined semantics?
- Published on 17 Jul 15

a. Enumeration
b. Iterator
c. None of the above
Answer  Explanation 

ANSWER: Iterator

Explanation:
No explanation is available for this question!

5)   Filtered streams are simply wrappers around underlying input or output streams that transparently provide some extended level of functionality.
- Published on 17 Jul 15

a. True
b. False
Answer  Explanation 

ANSWER: True

Explanation:
No explanation is available for this question!

6)   Where does the primitive data type values be stored?
- Published on 16 Jul 15

a. Heap Memory
b. Stack Memory
c. Both A & B
d. None of the above
Answer  Explanation 

ANSWER: Stack Memory

Explanation:
No explanation is available for this question!

7)   Which method returns an enumeration of the values contained in the dictionary?
- Published on 15 Jul 15

a. Enumeration elements()
b. Enumeration keys()
c. Enumeration propertyNames()
d. None of the above
Answer  Explanation 

ANSWER: Enumeration elements()

Explanation:
No explanation is available for this question!

8)   What package is a part of the wrapper class which is imported by default into all Java programs?
- Published on 15 Jul 15

a. java.lang
b. java.awt
c. java.io
d. java.util
Answer  Explanation 

ANSWER: java.lang

Explanation:
No explanation is available for this question!

9)   Wrapper classes are not used to convert any data type into an object.
- Published on 15 Jul 15

a. True
b. False
Answer  Explanation 

ANSWER: False

Explanation:
No explanation is available for this question!

10)   What method Returns an enumeration of the keys which includes those keys found in the default property list?
- Published on 13 Jul 15

a. Enumeration keys()
b. Enumeration elements()
c. Enumeration propertyNames()
d. Both A & B
Answer  Explanation 

ANSWER: Enumeration propertyNames()

Explanation:
No explanation is available for this question!
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