Full example for SO question @ http://stackoverflow.com/questions/14308275/why-does-this-generic-code-produce-a-nosuchmethoderror

Main.java

public class Main {
    public static void main(String[] args) {
        ensureLessThanWithCast(6, 5);
        ensureLessThan(6, 5);
    }

    public static <N extends Number & Comparable<N>, S extends N> S ensureLessThanWithCast(N threshold, S input) {
        if (((N) input).compareTo(threshold) >= 0) {
            throw new IllegalArgumentException("Input " + input + " is not less than " + threshold);
        }
        return input;
    }

    public static <N extends Number & Comparable<N>, S extends N> S ensureLessThan(N threshold, S input) {
        if (input.compareTo(threshold) >= 0) {
            throw new IllegalArgumentException("Input " + input + " is not less than " + threshold);
        }
        return input;
    }
}