double d = 123;
double e = 0;
if (d/e == Double.POSITIVE_INFINITY)
System.out.println("Check for POSITIVE_INFINITY works");
double s = Math.sqrt(-1);
if (s == Double.NaN)
System.out.println("Comparison with NaN incorrectly returns true");
if (Double.isNaN(s))
System.out.println("Double.isNaN() correctly returns true");