Is there a commonly used rational numbers library in Java?

Question

I\'m looking for a Java library which represents fractions (rational numbers). For example, if I want to store the fraction 1/3 then it will not be saved as

Answer 1

The JScience library includes the class org.jscience.mathematics.number.Rational. In addition to the usual factories, accessors and operations, one can construct other useful entities, including Polynomial, Vector and Matrix.

As an example, a function to obtain the lowest common denominator of a collection of fractions might look like this:

private static LargeInteger lcd(Collection fractions) {
    Rational sum = Rational.ZERO;
    for (Rational rational : fractions) {
        sum = sum.plus(rational);
    }
    return sum.getDivisor();
}

The following statement prints 6:

System.out.println(lcd(Arrays.asList(
    Rational.valueOf(1, 2), Rational.valueOf(1, 3))));