java.lang.Double.isNan(double v) java.lang.Double.isNan() java.lang.Double.longBitsToDouble() java.lang.Double.isNan(double v) package com.codingdict; import java.lang.*; public class DoubleDemo { public static void main(String[] args) { Double d1 = new Double(-1.0/0.0); Double d2 = new Double(0.0/0.0); // returns true if this Double value is a Not-a-Number (NaN) System.out.println(d1 + " = " + d1.isNaN(d1)); // returns false for other cases System.out.println(d2 + " = " + d2.isNaN(d2)); } } java.lang.Double.isNan() java.lang.Double.longBitsToDouble()