Multiple Choice Questions:
1) Which of the following is an example of a wrapper class?
a) Double
b) int
c) String
d) System
Answer: a.
2) In order to declare a named constant, the declaration must use which Java keyword?
a) final
b) int
c) static
d) void
Answer: a.
3) If x is a variable of type int, what is the largest possible value of the expression (x % 5) ?
a) 1
b) 4
c) 5
d) 231 – 1
Answer: b.
4) What is the meaning of the declaration: String [][] a = new String [60][80]; ?
, a) Create an array of 60 strings, each of size 80 characters.
b) Create an array of 80 strings, each of size 60 characters.
c) Create a two-dimensional array of strings with 60 columns and 80 rows.
d) Create a two-dimensional array of strings with 60 rows and 80 columns.
Answer: d.
5) Which of the following loop headers will arrange for the loop body to execute exactly 10 times?
a) for (int i = 1; i < 10; ++i)
b) for (int i = 0; i <= 10; ++i)
c) for (int i = –5; i < 5; ++i)
d) for (int i = 2; i < 20; ++i)
Answer: c.
6) What type of Java statement allows you to use classes contained in other packages?
a) an access statement
b) a class statement
c) an import statement
d) a package statement
Answer: c.
7) Which access modifier, used when defining a method, indicates that only one such method is
available for all instances of the class?
a) final
b) private
c) protected
d) static
Answer: d.
,8) Suppose c1 and c2 are objects of the class Circle. A Circle has a single data member, its radius.
The Circle class has a default constructor (implemented correctly), but no other methods have
been defined in the implementation of the Circle class. What will happen when we try to execute
this code?
Circle c1 = new Circle(12.0);
Circle c2 = new Circle(12.0);
boolean same = (c1.equals(c2));
a) The code will not compile because equals( ) has not been implemented in Circle.
b) The value of same will be true.
c) The value of same will be false.
Answer: c.
9) Suppose a String variable s is initialized to the value “inheritance”. What value is returned by
the call s.substring(2, 5) ?
a) nher
b) nheri
c) her
d) heri
Answer: c.
10) Which type of loop is guaranteed to execute its body at least once?
a) do-while
b) for
c) switch
d) while
Answer: a.
11) Which of these expressions is illegal in Java?
a) x++ 5
, b) x =+ 5
c) x += 5
d) x == 5
Answer: a.
12) Suppose s is of type String. What would it mean if s.lastIndexOf(s.charAt(0)) returns the
value 1?
a) The first character appears once in the string.
b) The first two characters in the string are identical.
c) The length of the string is 2.
d) The second character of the string is ‘0’.
Answer: b.
13) If s1 is of type String, what does s1.compareTo(s1) return?
a) zero
b) true
c) false
d) Cannot be determined without knowing the value of s1.
Answer: a.
14) How many constructors can a class have?
a) Exactly one
b) At least one but no more than three
c) Exactly the same as the number of data members
d) There is no restriction on the number of constructors
Answer: d.