instanceof

[adam Lui]

class ArrayInstanceTest {
public static void main (String args[]) {
int[] a = null;
WhichArray(a);


}
public static void WhichArray (Object x) {
if (x instanceof int[])
{
int[] n = (int[]) x ;
System.out.println("inside int test");
for (int i = 0; i<n.length; i++) {
System.out.println("integers = " + n[i]);
}
}
 if (x instanceof String[])
 {
 System.out.println("Array of Strings");
 }
 }
}

It compiles fine but there is no output. I expected at least "inside int test".
I am passing an int[] array into the method, checking if it is an instance of int[], and was pretty sure it will be true.

what is the problem here?!

[Kelvin Chenhao Lim]

Although null is a valid value for any reference variable, it is not an instance of any type. In other words, Java defines "null instanceof Type" to always be false, for any class or interface Type.