DoubleParse(String) returns the correct value plus 1 for 10e86

Tearing my hair out here. With my large number example Double.ParseDouble(String "10e86") returns 10e87. Here's an example debugger screen.

Thanks.

Heres the code as an rtf file:

public class HelloWorldApp
{


static double oops()
{
    String s = "10e86";
    double d = 0;

    System.out.println("Before ParseDouble s is " + s + " d  is " + d);

    d = Double.parseDouble(s);

    System.out.println("After ParseDouble s is " + s +  " d is " + d);
    return d;
}



    public static void main(String[] args)
    {

        double mainD = oops();
        System.out.println("main: oops() returns " + mainD);



    }
}