question on instanceof operator..

[Ganeshkumar cheekati]

source:www.jchq.net


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 wrapper class.
3)The instanceof operator wil;l 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..

can anyone answer this with explanation?

[arulk pillai]

Try some examples and see if you could figure this out. If you do that you will remeber this better for example try the option 2 as

  class test {
 
public static void main(String[] args) {
Integer i = new Integer(5);
if (i instanceof Object) {
System.out.println("Testing instanceof on wrapper ..............");
}
}
}
  

Integer is a wrapper class. Here is another hint

You use the instanceof operator to test if an object is a subclass of a specific class or implements a specific interface.

Also, try the other options via code.