In Java, why are the following results different?

Double:

double x1 = 279_632_249;
double a1 = (x1 * x1);
System.out.println(printDouble(a1));  // 78194194680798000

Long:

long x2 = 279_632_249;
long a2 = (x2 * x2);
System.out.println(a2);  // 78194194680798001

Utility function

private static String printDouble(double d) {
    BigDecimal bigDecimal = new BigDecimal(Double.toString(d));
    return bigDecimal.toPlainString();
}

Numbers greater than 279_632_249 will also differ. Is there a limit at 279_632_248?