[wheaties]

I hate to break it to you but "n" is not final. Hence, you can reassign any BigInteger to it. Why not just set n = 9 and the root = 3...

Immutability is your friend. Use it or lose it.

[craigching]

But n is also private, so you can't reassign it without using setAccessible or changing the security manager, both forbidden by the rules.

[coolbrow]

But "n" is private and the rules state the solution must be in a different class. Thus you can't simply reassign it.

[tantalor]

You can't assign anything to a private variable.