How to see if an object is an array without using reflection?

How can I see in Java, if an Object is an array and how can I iterate through all items without using reflection?

I use Google GWT so I am not allowed to use reflection :-(

I would love to implement the following methods without using refelection:

private boolean isArray(final Object obj) {
  //??..
}

private String toString(final Object arrayObject) {
  //??..
}

BTW: neither do I want to use JavaScript such that I can use it in non-GWT environments.