Answer:
1. Which of the following is not the name of a Java wrapper class from the Java API?
A. Byte
B. Int
C. Long
D. Boolean
Int is not a wrapper class
Byte is the wrapper class of byte, Int is not a wrapper class and is a primitive data type, Long is a wrapper class of long, Boolean is a wrapper class for boolean. Hence Int is the correct answer and its wrapper class is Integer.
2. Which of the following statements will cause a compiler error?
A. Integer i = new integer ( ) ;
B. Integer j = new integer ("5") ;
C. Integer k = Integer.valueOf ("5");
D. int m = Integer.pareseInt ("5");
“I” in integer in A and B must be in capital.
3. If variables j and k refer to objects of type Double and j . compareTo (k) returns a value of 1, which of the following is true?
A. The double value held in j is less than the value held inside k.
B. The difference between values held in j and k is 1.
C. The double values held inside j and k are both positive.
D. The double value held inside j is greater than the value held inside k.
Compareto return 1 if first value is greater than with what it is compared.
4. What is a radix as used in the method parseInt (String s, int radix) from the integer class?
A. A numeric base 2 such as for binary or 16 for hexadecimal.
B. The number of characters in the string that represent integers.
C. The Unicode character code to be used when parsing the string.
D. The number of times the string should be repeated before being converted to an int.
The radix value is 10 for decimal, 2 for binary and 16 for hexadecimal. Radix is the base or number of unique digits.
5. Which of the following is a static method of the integer class?
A. intValue ( )
B. parseInt ( )
C. toString ( )
D. compareTo ( )
ParseInt() is a static method of the integer class, and rest are non static methods.
6. Which of the following statements will cause a compiler error?
A. Double a = new Double (10.6) + 3;
B. Integer b = 0;
C. Double c = 0;
D. int d = new Integer (7) ;
In A and C data type does not matches like Double c=0 means Double c=new int(0) which is never true.
7. Which of the following is not an example of autoboxing?
A. Boolean a = false
B. Integer b = new integer (9);
C. double x = 3.0;
Double c = x;
D. Character d = ‘2’;
Autoboxing brings out reference type from the value type, and this is not true for A
8. What is the result of the following code fragment?
BigInteger a = new BigInteger (“10”);
BigInteger b = new BigInteger (“25”);
a . multiply (b);
a . add (b);
System.out.println (a);
A. 10
B. 35
C. 250
D. 275
a.multiply(b) = 250
a.add(b)= 250+25=275
9. What is the name of the BigInteger method that will calculate the remainder of division by another BigInteger?
A. modulo ( )
B. modulus ( )
C. divisor ( )
D. remainder ( )
Remainder is the correct answer.
Explanation:
Please check answer.
