InputStream vs Reader

Question

I am going over input output section and there are so much classes and interfaces that I am confused a little bit.
As documentation says InputStream is a byte based stream whereas Reader is character-based stream. But as I understood correctly the only difference between them is that Reader reads two bytes per time instead of one byte at a time as InputStream does.
Therefore I don't understand is there any difference:
Using InputStream

 byte[] bytes = new byte[2];
    InputStream in = new FileInputStream("input.txt");
    int bytesRead = in.read(bytes);
    while(bytesRead != -1) {
      doSomethingWithData(data);
      bytesRead = inputstream.read(data);
    }

Using Reader

Reader reader = new InputStreamReader(new FileInputStream("input.txt"));
int data = reader.read();
while (data != -1) {
   doSomethingWithData(data);
   data = reader.read();
}

I am really confusing about these aspects. Explain please in details. Thanks.

Answer 1

You can use a Reader to read text data. And it's supports some character encoding like - ISO, UTF-8. If you want to read a text file with some encoding then you can use Readers like - BufferedReader, StringReader etc.

And you can use Stream (InputStream, OutputStream) to manipulate binary data. For example you want to read a image file then you can use FileInputStream and when you want to save it to disk then you can use FileOutputStream.