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Data Types in Java - MCQ Questions with Answers - Core Java Quiz

(1) Which of the following is not an valid declaration of an array?
[A] int [ ] a = new int [3];
[B] int a [ ] [ ] = new int [3] [3]
[C] int [ ] [ ] a = new int [3] [ ];
[D] int [ ] [ ] a = new int [ ] [3];

Comment

Answer: Option [D]

In multidimensional array rows cannot left blank.

(2) String.ValueOf('r').concat("def").concat(String.ValueOf('2'))
[A] 0
[B] 1
[C] 3
[D] 4

Comment

Answer: Option [B]
(3) Which of the following is correct statement?
[A] Boolean true value is 1 and false value is 0
[B] Every private class has a wrapper class
[C] Constant identifier precede with a reserved word final
[D] System.out.println() method also flushes the buffer

Comment

Answer: Option [C]

Constants are not directly supported by Java. The reserved 'Final' is used to declare constant.

(4) Size of an integer can be
[A] -231 to 231-1
[B] 0 to -216
[C] -28 to 28-1
[D] -215 to 215-1

Comment

Answer: Option [A]

Int takes 4 bytes i.e. 32bits. 1 bit is reserved to store sign.

(5) For which of the following data types the ValueOf() method is NOT overloaded in the string class?
[A] Float
[B] Boolean
[C] Object
[D] None of these

Comment

Answer: Option [D]

For all Java built in types ValueOf() method is overloaded within the String. valueOf() method returns the string representation of the corresponding arguments value.

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