Send a file from Android to Java Server

Android - sendFile.java

//first you need to create a socket and connect with a socket then use the following code
private OutputStream out = socket.getOutputStream();;

//you need to use the file you want to send as a param
public void sendMessage(File file) throws IOException {
        if (out != null) {
            byte[] bytes = new byte[(int) file.length()];
            BufferedInputStream bis;
            bis = new BufferedInputStream(new FileInputStream(file));
            bis.read(bytes, 0, bytes.length);
            ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());
            oos.writeObject(bytes);
            out.flush();
        }
    }

Java - receiveFile.java

//you need to be connected with a socket from where you will receive the files, then use the following code

//stream to receive the files
private StreamConnection mConnection;

InputStream inputStream   = mConnection.openInputStream();
ObjectInputStream ois     = new ObjectInputStream(inputStream);

//receiving the file
public void receiveFile(){
    try {
      ois = new ObjectInputStream(inputStream);
      byte[] bytes;
      FileOutputStream fos = new FileOutputStream("C://temp//yourFile.jpg"); //path to save the file, it can be any extension you want
  
      try {
          bytes = (byte[]) ois.readObject();
          fos.write(bytes);
      } catch (ClassNotFoundException e) {
          e.printStackTrace();
      } finally {
          if (fos != null) {
              fos.close();
              System.out.println("File Received!");
          }
      }
    } catch (FileNotFoundException ex) {
        Logger.getLogger(ProcessConnectionThread.class.getName()).log(Level.SEVERE, null, ex);
    } catch (IOException ex) {
        Logger.getLogger(ProcessConnectionThread.class.getName()).log(Level.SEVERE, null, ex);
    }
}