Java – How to convert byte array to PDF file in Android?

I’m developing an application that gets data as a byte array that I need to use to create a new PDF file. How do I implement this in Android?

This is one of the methods to create a PDF from a byte array.

File dir = Environment.getExternalStorageDirectory();
File assist = new File("/mnt/sdcard/Sample.pdf");
try {
  InputStream fis = new FileInputStream(assist);

long length = assist.length();
  if (length > Integer.MAX_VALUE) {
    Log.e("MainActivity", "cannnottt   readddd");
  }
  byte[] bytes = new byte[(int) length];
  int offset = 0;
  int numRead = 0;
  while (offset < bytes.length && (numRead = fis.read(bytes, offset, bytes.length - offset)) >= 0) {
    offset += numRead;
  }

File data = new File(dir, "mydemo.pdf");
  OutputStream op = new FileOutputStream(data);
  op.write(bytes);
} catch (Exception ex) {
  Log.e("MainActivity", "" + ex.getMessage())
}