How can “while (i == i) ;” be a non-infinite loop in a single threaded application?

Question

I just got a question that I can\'t answer.

Suppose you have this loop definition in Java:

while (i == i) ;

What is the type of

Answer 1

Since others said it's NaN I got curious about the official (JDK 6) implementation of Double.isNaN, and behold:

/**
 * Returns true if the specified number is a
 * Not-a-Number (NaN) value, false otherwise.
 *
 * @param   v   the value to be tested.
 * @return  true if the value of the argument is NaN;
 *          false otherwise.
 */
static public boolean isNaN(double v) {
    return (v != v);
}