FileWriter vs FileOutputStream in Java

A FileOutputStream writes bytes directly. A FileWriter encapsulates a FileOutputStream (by creating it in the FileWriter constructor as in your question) and provides convenience methods to write characters and Strings.

FileWriter is a Writer. It's about writing text - and it happens to be writing it to a file. It does that by holding a reference to a FileOutputStream, which is created in the FileWriter constructor and passed to the superclass constructor.

FileOutputStream is an OutputStream. It's about writing binary data. If you want to write text to it, you need something to convert that text to binary data - and that's exactly what FileWriter does. Personally I prefer to use FileOutputStream wrapped in an OutputStreamWriter by me to allow me to specify the character encoding (as FileWriter always uses the platform default encoding, annoyingly).

Basically, think of FileWriter is a simple way of letting you write:

Writer writer = new FileWriter("test.txt");

instead of

Writer writer = new OutputStreamWriter(new FileOutputStream("test.txt"));

Except I'd normally recommend using the overload of the OutputStreamWriter constructor that accepts a Charset.

FileOutputStream is to write primitive types of data, like int, while FileWriter is to write character-oriented data.

FileOutputStream does not come with methods to deal with strings. If you want to use FileOutputStream to write a string to a file, you have to go like:

FileOutputStream fos=new FileOutputStream();
String str="Hello";
byte b[]=str.getBytes();
fos.write(b);
fos.close();

In Filewriter there is no conversion between string and byte array. You could simply use:

FileWriter fr=new FileWriter("C:\\");
fr.write("Hello");
fr.close();

Do not forget to throw any exceptions if needed.