title: java.io.IOException: Read-only file system
body: <pre><code>File mediaDir = new File("media");
  if (!mediaDir.exists()){
      mediaDir.createNewFile();
      mediaDir.mkdir();
  
  }
  
  File f = new File("/data/data/com.test.image/files/media/Voucher.jpg");
  f.createNewFile();
  FileOutputStream fos = new FileOutputStream(f);
  fos.write(b);
  fos.close();
  </code></pre>
  
  <p>Try to write a file in phone internal memory but it throw an error: <strong>java.io.IOException: Read-only file system</strong></p>