java URL对象使用错误

前段时间我使用用java写一个多线程下载工具，使用URL对象时发现在子线程中URL对象创建后，程序直接退出，我改到主线程中就没有任何问题。

package filedownload;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;
import java.util.logging.*;

public class FileDownLoad implements Runnable {
    private String fileURL;
    private Logger logger;
    public FileDownLoad(String url){
        fileURL = url;
        logger = Logger.getLogger("filedownload");
        logger.setLevel(Level.INFO);
    }

    @Override
    public void run() {
        String fileBasename = fileURL.substring(fileURL.lastIndexOf("/")+1);
        try{
            logger.info("DownLoad form"+ fileURL);
            URL url =  new URL("http://github.com/orhanobut/logger/archive/master.zip");
            String loacalURL = "/home/sosky/"+fileBasename;
            logger.info("saving in "+ loacalURL);
            DownLoadFromURL(url, new FileOutputStream(loacalURL),1024);
        } catch(Exception e){
            e.printStackTrace();
            logger.info(e.toString());
        }
    }
    //测试函数
    public void test(URL url, String loacal){
        try {
            DownLoadFromURL(url, new FileOutputStream(loacal),1024);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    private void DownLoadFromURL(URL url, FileOutputStream outputStream , int bufSize)
            throws MalformedURLException,IOException{
        final HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");
        ReadableByteChannel read = null;
        WritableByteChannel write = null;

        try{
            int respon = connection.getResponseCode();
            if (2!=(respon/100)){
                throw new  IOException("Http exception :"+respon);
            }
            if (0==connection.getContentLength()){
//               throw new IOException("nothing to download!!!");
                logger.info("nothing to download!!!");
                return;
            }
            read = Channels.newChannel(new BufferedInputStream(connection.getInputStream()));
            write = Channels.newChannel(new BufferedOutputStream(outputStream));
            ByteBuffer byteBuffer = ByteBuffer.allocate(bufSize);
            while(-1!=read.read(byteBuffer)){
                byteBuffer.flip();
                write.write(byteBuffer);
                byteBuffer.clear();
            }
        }finally{
            silentClose(read,write);
        }
    }

    public static void silentClose(Closeable... closeable) {
        if (null == closeable) {
            return;
        }
        for (Closeable c : closeable) {
            if (null == c) {
                continue;
            }
            try {
                c.close();
            } catch (Exception ignored) {
            }
        }
    }
}

测试类如下：

public class filedownloadtest {
    /**
     * URL对象在子线程创建过程中会导致程序退出，切且返回码为0，没有抛出任何异常，待解决
     */
    @ToBeSolved(date="sosky",methodName = "download",className = "filedownloadtest",
            desicripition = "URL对象在子线程创建过程中会导致程序退出，切且返回码为0，没有抛出任何异常")
    @Test
    public void download(){
        String url = "http://github.com/orhanobut/logger/archive/master.zip";
        Thread downThread = new Thread(new FileDownLoad(url));
        //downThread.start();
    }

    /**
     * URL对象创建主线程中创建成功
     */
    @Test
    public void mainthread(){

        try {
            FileDownLoad downLoad = new FileDownLoad("123");
            URL url = new URL("https://github.com/square/leakcanary/archive/master.zip");
            downLoad.test(url,"/home/sosky/master.zip");
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }

    }
}

结语

URL对象应创建主线程中，在子线程中创建会导致程序貌似正常退出，但是后面的代码都不执行，具体原因我还不清楚，有大佬知道望告知。