Question

I am facing the problem similar to How to Force a jar to uses(or the jvm runs in) utf-8 instead of the system’s default encoding. There is a server and client java applications. If I run both of them from Eclipse then everything works just fine. If I make jars then a String exchanged between them gets spoiled (wrong encoding).

If I run both images with -Dfile.enconding=utf-8 JVM parameter then it works okay. But since the link above says that it is not the best solution (at least requires running jar from bat) I have tried to solve the issue with specifying encoding to BufferedReader. But it fails and with jar it is difficult to debug.

This code is for sending request and getting one line in JSON format as reply. The reply is proved to have UTF-8 encoding.

public static String sendRequest (String request) {
    if (request == null) return null;

    try {
        URL url = new URL(request);
        HttpsURLConnection con = (HttpsURLConnection)url.openConnection();
        BufferedReader inReader = new BufferedReader(new InputStreamReader(con.getInputStream(), Charset.forName("UTF-8")));
        String line = inReader.readLine();
        inReader.close();
        return line;
    } catch (Exception e) {
        e.printStackTrace(System.err);
    }

    return null;
}

This is how the line look like

{“response”:[{“uid”:123456,”first_name”:”Имя”,”last_name”:”Фамилия”}]}

Then I prepare it to use in Gson.fromJson()

int beginIndex = reply.indexOf('[');
int endIndex = reply.indexOf(']');
reply = reply.substring(beginIndex + 1, endIndex);
SocialPerson vkPerson = new Gson().fromJson(reply, SocialPerson.class);

After that the String is being sent to server using Netty’s ChannelBuffer generated with ChannelBuffers.wrappedBuffer() and NettyUtils.writeStrings()

I try to debug Client in Eclipse and Server running from jar, then Eclipse shows that until the string is really given to framework to deliver it looks valid.

Then I debug Server and Client runs from Jar and once string being received it already looks like rubbish.

At server side

    private final String username;
    private final String password;

    public SimpleCredentials(ChannelBuffer buffer)
    {
        this.username = NettyUtils.readString(buffer);
        this.password = NettyUtils.readString(buffer);
    }

Where do you think the problem can be? Sorry, I can not post all the code here.

UPD:
username is generated from firstName and lastName

ChannelBuffer buffer = ChannelBuffers.wrappedBuffer(opCode, NettyUtils.writeStrings(userId, userName, refKey));

Answer 1

You shouldn’t be using the file.encoding system property.

The best way to avoid such encoding issues is to never assume anything about default platform encodings and always provide an encoding when constructing readers or when converting bytes to Strings and vice versa.

Your sendRequest method seems to be OK with respect to handling encodings: it reads characters from the input, explicitly mentioning that it expects the stream to be encoded in UTF-8.

However, we can’t see the other end of the client/server sequence. Quoting you:

After that the String is being sent to server using Netty’s
ChannelBuffer generated with ChannelBuffers.wrappedBuffer() and
NettyUtils.writeStrings()

You also mentioned that you can’t attach the entire code here, which is understandable; therefore, I’d advise that you look into how exactly you’re sending those strings out, and whether or not you’re explicitly specifying an encoding while doing so.

EDIT as per OP’s update: well, I’m sorry that I am not familiar with Netty, but still I’ll take a shot here. Doesn’t NettyUtils.writeStrings(), or any of the code that calls it, accept a character encoding? I can’t find the JavaDoc to any NettyUtils online. Work with me here. 🙂