public static <T extends Comparable<?>> T max(T a, T b) {
    if (a == null) {
        if (b == null) return a;
        else return b;
    }
    if (b == null)
        return a;
    return a.compareTo(b) > 0 ? a : b;
}

The method compareTo(capture#5-of ?) in the type Comparable<capture#5-of ?> is not applicable for the arguments (T)

<dependency>
    <groupid>org.softsmithy.lib</groupid>
    <artifactid>lib-core</artifactid>
    <version>0.1</version>
</dependency>

public static <T extends Comparable<T>> T max(T a, T b) {
    if (a == null) {
        if (b == null) return a;
        else return b;
    }
    if (b == null)
        return a;
    return a.compareTo(b) > 0 ? a : b;
}