// This rule specifies whether you have to provide
// a @return tag for the return value declared in
// the method.
// Method returning void should not have a @return
// tag since they do not return anything.

...
public class MonteCarloMethod
{
    ...

    /**
     * calculate PI to the n-the decimal
     * using the monte carlo method
     *
     * @param n number of decimals
     * @return PI to the n-decimal
     */
    public double pi(int n)
    {
        ...