The function endsWith in standard library returns false also when the searched
substring is contained twice in string. 
Example : fn:endsWith( 'abcdb' ,'b' ) returns false.

Original source code :

    public static boolean endsWith(String input, String substring) {
        if (input == null) input = "";
        if (substring == null) substring = "";
        int index = input.indexOf(substring);
        if (index == -1) return false;
        if (index == 0 && substring.length() == 0) return true;
        return (index == input.length() - substring.length());
    }  

should be :

    public static boolean endsWith(String input, String substring) {
        if (input == null) input = "";
        if (substring == null) substring = "";
        int index = input.lastIndexOf(substring);
        if (index == -1) return false;
        if (index == 0 && substring.length() == 0) return true;
        return (index == input.length() - substring.length());
    }