title: uncaught exception 'NSFileHandleOperationException'
body: <p>I am trying to dowload simultaneously several files from my own server while using this code : </p>
  
  <pre><code>- (void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
  {
      // create
      [[NSFileManager defaultManager] createFileAtPath:strFilePath contents:nil attributes:nil];
      _file = [NSFileHandle fileHandleForUpdatingAtPath:strFilePath];// read more about file handle
      if (_file)   {
          [_file seekToEndOfFile];
      }
  }
  
  - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)receivedata
  {
      //write each data received
      if( receivedata != nil){
          if (_file)  {
              [_file seekToEndOfFile];
          }
          [_file writeData:receivedata];
      }
  }
  
  - (void)connectionDidFinishLoading:(NSURLConnection*)theConnection {
      //close file after finish getting data;
      [_file closeFile];
  }
  
  - (void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
  {
      //do something when downloading failed
  }
  - (IBAction)downloadFromServer:(id)sender {
  
          NSLog(@"File now being downloaded");
      while (i&lt;=3) {
  
      NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
      NSURL *strFileURL =[NSURL URLWithString:[NSString stringWithFormat:@"SomePath/pic%d.png", i]];
  
      [request setURL:strFileURL]; 
      NSURLConnection *conection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
      [conection start];
      strFilePath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:[NSString stringWithFormat:@"pic%d.png", i]];
  
      }
  
  }
  </code></pre>
  
  <p>I have 3 pictures , pic1.png , pic2.png and pic3.png. Now if i run this code, the app will only save one corrupted file named pic3.png and automatically crashes. I need to download all three files, any pointers where i am going wrong? </p>