24. Testing if a double number is an integer

First of all, let’s consider the following expected results (false means that the double is not an integer):

double v1 = 23.11;                    // false
double v2 = 23;                       // true
double v3 = 23.0;                     // true
double v4 = Double.NaN;               // false
double v5 = Double.NEGATIVE_INFINITY; // false
double v6 = Double.POSITIVE_INFINITY; // false

Most probably, the first solution for testing if a double number is an integer consists of a simple cast as follows:

public static boolean isDoubleIntegerV1(double v) {
  return v == (int) v;
}

However, there are several other options. For instance, we can rely on modulus, as follows:

public static boolean isDoubleIntegerV2(double v) {
  return v % 1 == 0;
}

Alternatively, we can rely on the Math.floor() and Double.isFinite() methods. If the given double is a finite number and is equal to the result of Math.floor(), then...