使用jar文件中的代码时出现问题

public class Sign {

private static final PrivateKey         priv    = Util.loadPrivate();
private static final PublicKey          pub     = Util.loadPublic();
private static final HexBinaryAdapter   adp     = new HexBinaryAdapter();

public static String sign(String in) {
    try {
        Signature sign = Signature.getInstance(Util.ALG);
        sign.initSign(priv);
        sign.update(in.getBytes());
        return adp.marshal(sign.sign());

    } catch (Exception e) {e.printStackTrace();}
    return null;
}

public static boolean verify(String data, String sign) {
    try {
        Signature verify = Signature.getInstance(Util.ALG);
        verify.initVerify(pub);
        verify.update(data.getBytes());
        return verify.verify(adp.unmarshal(sign));
    } catch (Exception e) {e.printStackTrace();}
    return false;
}

    public static void main(String[] args) {
    String in = \"lala\";
    String sign = Sign.sign(in);
    System.out.println(sign);
    System.out.println(Sign.verify(in, sign));
}

    public static PrivateKey loadPrivate() {
    try {
        URLConnection con = Util.class.getResource(\"private.key\").openConnection();
        byte[] bs = new byte[con.getContentLength()];
        con.getInputStream().read(bs);
        return KeyFactory.getInstance(ALG).generatePrivate(new PKCS8EncodedKeySpec(bs));
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
}

public static PublicKey loadPublic() {
    try {
        URLConnection con = Util.class.getResource(\"public.key\").openConnection();
        byte[] bs = new byte[con.getContentLength()];
        con.getInputStream().read(bs);
        return KeyFactory.getInstance(ALG).generatePublic(new X509EncodedKeySpec(bs));
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
}