The equivalent of instanceof

Question

What is the equivalent of this without using instanceof? Maybe something more simple while using true, false or else statements?

public static void p (Object...ar)
{
        for (int i=0; i < ar.length; i++)
        {
                if (ar[i] instanceof int[])
                {

Answer 1

For primitive arrays you can, instead of:

if (ar[i] instanceof int[])

Use:

if (ar[i].getClass() == int[].class)

Note: The above code works fine for arrays of primitive types. Please be aware, though, that instanceof also checks if the object in the left-part is a subtype of the class in the right-part, while == does not.
For objects , the equivalent to (myInstance instanceof MyClass[]) (checks for subtyping) is:

(   MyClass[].class.isAssignableFrom(  myInstance.getClass()  )   )

Answer 2

You could use:

(getClass().isArray())

and checking if integer array:

 ar.getClass().toString().equals("class [I")

updated :

if(ar.getClass().isArray()) {
        if(ar[i].getClass() == int[].class)
            ....
        else if(ar[i].getClass() == String[].class)
            ....
}

Answer 3

Another option would be to just assume it is an int[] , and catch the resulting exception if it is not:

public static void p (Object...ar)
{
    for (int i=0; i < ar.length; i++)
    {
        int[] i_arr;
        try {
            i_arr = (int[]) ar[i];
        } catch (ClassCastException e) {
            continue;
        }
        //...

Answer 4

Generally, inheritance and polymorphism is a better solution to your problem. Rather than check what kind of object you are dealing with, have several classes inherit from a generic class, and call the shared methods.

Answer 5

Check out java.lang.Class, which has a method isAssignableFrom(Class<?> cls)

For your specific example with arrays, it also has isArray() and getComponentType()

Answer 6

Class<?> intArrayCls = int[].class;

...

if (intArrayCls.isInstance(ar[i])) {

Would do the trick too.

JavaDoc of isInstance . It is a little more flexible as it doesn't just test equality like the accepted answer.

Answer 7

use isAssignableFrom

public static void test(Object... args) {
    for (int i = 0; i < args.length; i++) {
       if (args[i].getClass().isAssignableFrom(int[].class)) {
        System.out.println("true");
       } else {
            System.out.println("false");
       }
    }
}

you can use isAssignableFrom in a dynamic way too, see this post to know the difference between instanceof and isAssignableFrom What is the difference between instanceof and Class.isAssignableFrom(...)?