Ошибка для загрузки кучу файлов с сервера

Question

Я пытаюсь кучу файлов с сервера с помощью AsynchTask я получил эту ошибку:

07-09 12:49:57.868: E/AndroidRuntime(11133): java.lang.ExceptionInInitializerError 
07-09 12:49:57.868: E/AndroidRuntime(11133): Caused by: java.lang.NullPointerException 

Он бросает меня на этой линии:

public static final Executor THREAD_POOL_EXECUTOR = new ThreadPoolExecutor(CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE, null, null); 

я не знаю, Что проблема .. мой код

package com.soch.webservice; 

import java.io.BufferedReader; 
import java.io.File; 
import java.io.FileOutputStream; 
import java.io.FileReader; 
import java.io.IOException; 
import java.io.InputStream; 
import java.net.URL; 
import java.net.URLConnection; 
import java.util.ArrayList; 
import java.util.concurrent.Executor; 
import java.util.concurrent.ThreadPoolExecutor; 

import android.app.Service; 
import android.content.ContentValues; 
import android.content.Intent; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.os.AsyncTask; 
import android.os.Environment; 
import android.os.IBinder; 
import android.util.Log; 

import com.soch.database.Database_Handler; 

public class FileTransferService extends Service { 

    private static final int CORE_POOL_SIZE = 2; 
    private static final int MAXIMUM_POOL_SIZE = 5; 
    private static final int KEEP_ALIVE = 1; 

    public static final Executor THREAD_POOL_EXECUTOR = new ThreadPoolExecutor(CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE, null, null); 

    int FileNo = 0; 

    ArrayList<String> FileId = new ArrayList<String>(); 
    ArrayList<String> ServerPath = new ArrayList<String>(); 
    ArrayList<String> SynchPath = new ArrayList<String>(); 
    ArrayList<String> FileNameList = new ArrayList<String>(); 

    String FileTransferPath = "", SDcardPath = ""; 

    @Override 
    public void onCreate() { 
     super.onCreate(); 
     Log.d("Service Created", "Successfully"); 

     FileId.clear(); 
     ServerPath.clear(); 
     SynchPath.clear(); 
     FileNameList.clear(); 

     SDcardPath = Environment.getExternalStorageDirectory().getPath() + "/"; 

     // Get FileTransfer Link From The SD Card 
     ...... 

     // Getting A url From DB 

     ..... 

    }// End onCreate 

    @Override 
    public int onStartCommand(Intent intent, int flags, int startId) { 

     Log.d("Service Started", "Successfully"); 

     Log.d("fileSize",""+FileId.size()); 
     if (FileId.size() > 0) { 

      ContentValues mContentValuesUpdatefileStatus = new ContentValues(); 
      mContentValuesUpdatefileStatus.put("Status", 1); 

       while (FileNo < FileId.size()) { 

       try { 

        new DownloadFileFromURL().executeOnExecutor(THREAD_POOL_EXECUTOR,Integer.toString(FileNo));       

       } catch (Exception e) {  

        Log.e("File Error", " File id is " + FileId.get(FileNo) + " File path is " + ServerPath.get(FileNo) + " Synch Path is " + SynchPath.get(FileNo)); 
        FileNo += 1; 
        e.printStackTrace(); 
       } 

      } 

     } 

     Log.d("Service Finish", "Successfully"); 
     stopSelf(); 

     return super.onStartCommand(intent, flags, startId); 
    } 

    class DownloadFileFromURL extends AsyncTask<String, String, String> { 

     int Count = 0; 
     int File_Completed = 0; 
     int FileNo; 
     String strServerPath,strSynchPath,strFileName; 

     @Override 
     protected void onPreExecute() { 
      super.onPreExecute(); 

     } 

     @Override 
     protected String doInBackground(String... params) { 

      FileNo = Integer.parseInt(params[0]); 

      // Get File Path 
      strServerPath = ServerPath.get(FileNo).replaceAll(" ", "%20"); 
      strSynchPath = SynchPath.get(FileNo); 
      strFileName = FileNameList.get(FileNo); 

      URLConnection mConnection = null; 

      Log.d("file", strSynchPath + strFileName); 

      File SynchPath = new File(strSynchPath); 
      if (!SynchPath.exists()) { 
       SynchPath.mkdirs(); 
      } 

      try { 

       URL url = new URL(strServerPath); 
       mConnection = url.openConnection(); 
       mConnection.connect(); 

       // getting file length 
       int lenghtOfFile = mConnection.getContentLength(); 

       // Output stream to write file 
       File outputFile = new File(SynchPath, strFileName); 
       FileOutputStream mFileOutputStream = new FileOutputStream(
         outputFile); 

       InputStream mInputStream = url.openStream(); 
       byte data[] = new byte[1024]; 

       long File_Completed_Size = 0; 

       while ((Count = mInputStream.read(data)) != -1) { 

        File_Completed_Size += Count; 
        File_Completed = (int) ((File_Completed_Size * 100)/lenghtOfFile); 

        // writing data to file 
        mFileOutputStream.write(data, 0, Count); 
       } 

       // flushing output 
       mFileOutputStream.flush(); 

       // closing streams 
       mFileOutputStream.close(); 
       mInputStream.close(); 

      } catch (IOException IO) { 

       Log.e("File Exception"," File id is " + FileId.get(FileNo) + " File path is " + strServerPath + " Synch Path is " + strSynchPath + "FileName " + strFileName); 
       FileNo += 1; 
       IO.printStackTrace(); 

      } catch (Exception e) { 

       Log.e("File Exception"," File id is " + FileId.get(FileNo) + " File path is " + strServerPath + " Synch Path is " + strSynchPath + "FileName " + strFileName); 
       FileNo += 1; 
       e.printStackTrace(); 
      } 
      return null; 
     } 

     @Override 
     protected void onPostExecute(String result) { 
      super.onPostExecute(result); 

      if (File_Completed == 100) { 
       Log.d("File Downlode Status for " + SynchPath.get(FileNo), "" + File_Completed + "%"); 
       FileNo += 1; 
      } 
     } 
    } 

    @Override 
    public IBinder onBind(Intent intent) { 
     return null; 
    } 
} 

Отредактировано

private static final int CORE_POOL_SIZE = 2; 
private static final int MAXIMUM_POOL_SIZE = 5; 
private static final int KEEP_ALIVE = 1; 
private static final BlockingQueue<Runnable> sPoolWorkQueue = new LinkedBlockingQueue<Runnable>(3); 

public static final Executor THREAD_POOL_EXECUTOR = new ThreadPoolExecutor(CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE,TimeUnit.SECONDS, sPoolWorkQueue); 

Answer 1

От documentation вы можете увидеть возвращаемое значение:

Throws: IllegalArgumentException - if corePoolSize or keepAliveTime less than zero, or if maximumPoolSize less than or equal to zero, or if corePoolSize greater than maximumPoolSize. NullPointerException - if workQueue is null

Так, workQueue не может быть пустым