import com.dropbox.core.DbxRequestConfig;
import com.dropbox.core.v2.DbxClientV2;

import java.io.FileInputStream;
import java.io.InputStream;

public class Solution {

    public static void main(String[] args) {

        String ACCESS_TOKEN = "WcgiFB5RYMAAAAAAAAAAET8GW6a0VMfPnQgQg7F6dxVZlkf3ryBz7bEE4yo_FQ9l";

        DbxRequestConfig config = DbxRequestConfig.newBuilder("dropbox/java-tutorial").build();
        DbxClientV2 client = new DbxClientV2(config, ACCESS_TOKEN);


        try {
            InputStream in = new FileInputStream("C:\\Users\\Алексей\\Desktop\\test.txt");
            client.files().uploadBuilder("/test777.txt")
                    .uploadAndFinish(in);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}