Comparing two NaNs is not a good idea in Java

//w ww.  j a v  a2 s. c om
public class Main {
  public static void main(String[] argv) {
    // Comparing two NaNs is not a good idea:
    double d1 = Double.NaN;
    double d2 = Double.NaN;
    if (d1 == d2)
      System.err.println("Comparing two NaNs incorrectly returns true.");
    if (!new Double(d1).equals(new Double(d2)))
      System.err.println("Double(NaN).equal(NaN) incorrectly returns false.");
         
  }
}