Question

1.which of the following are methods of the JDK iterator interface?

a) hasNext()

b) next()

c) both a and b

d) neither a nor b

2.what is the purpose of the static method named instance() in a singleton class

a) to create the only instance of the singleton class (if needed) and return it

b) To receive the only instance of the singleton class as a parameter and store it in the field of the class

c) To query the user for the singleton instance and store it in a field of the class

d) none of the above

3. Using the adaptee pattern helps

a) improve code reuse

b)Allow client code to remain unchanged when a collection changes

c) Overcome the drawbacks of the object oriented paradigm

d) avoid class explosion

Answer 1

1)  c) both a and b
2)  a) to create the only instance of the singleton class (if needed) and return it
3)  b) Allow client code to remain unchanged when a collection changes