@JRubyMethod(name = {"append", "<<"}, required = 1)
public IRubyObject append(IRubyObject obj) {
    String ss = obj.convertToString().toString();
    try {
        URL url = getURL(ss);
        getRuntime().getJRubyClassLoader().addURL(url);
    } catch (MalformedURLException mue) {
        throw getRuntime().newArgumentError(mue.getLocalizedMessage());
    }
    return this;
}