格林模拟试题三（上）(2)

   
question 6) 
which of the following statements are true? 
1) the instanceof operator can be used to determine if a reference is an instance of a class, but not an interface. 
2) the instanceof operator can be used to determine if a reference is an instance of a particular primitive wrapper class 
3) the instanceof operator will only determine if a reference is an instance of a class immediately above in the hierarchy but no further up the inheritance chain 
4) the instanceof operator can be used to determine if one reference is of the same class as another reference thus

question 7) 
1) an interface can only contain method and not variables 
3) a class may extend only one other class and implement only one interface 

question 8) 
1) public class mycalc extends math 
3) math.round(9.99,1); 

question 9) 
1) run 
3) yield