httpservices/src/main/java/ucar/httpservices/HTTPUtil.java
static public String nullify(String s)
    {
        if(s != null && s.length() == 0) s = null;
        return s;
    }
static public String nullify(String s)
    {
        if(s != null && s.length() == 0) s = null;
        return s;
    }
Convert a zero-length string to null

@param s the string to check for length
@return null if s.length() == 0, s otherwise