Is PrintWriter Buffered?

[Alec Lee]

If we want buffered output to a file, should we wrap the printWriter around
a BufferedWriter like this:

BufferedWriter bw=new BufferedWriter(new FileWriter(args[1]));
    PrintWriter pw=new PrintWriter(bw,true);
    pw.println("something");
    

The javadoc doesn't mention if PrintWriter is buffered or not. I want to use PrintWriter for writing formatted text string to a file but want it to be buffered.

[Ulf Dittmer]

Since you're using a BufferedWriter, it doesn't matter much whether the PrintWriter is buffered (and I think it isn't, because that's what BW is for). The important thing is that the data does get buffered before being written to disk, and that's what happens here.

[Alec Lee]

Thanks for your advice. Actually, I'm worrying about buffering twice if PrintWriter already buffered.

[Ilker Tasci]

Yes the PrintWriter is buffered.

See my little test code below:

            PrintWriter pw = new PrintWriter(System.out);
            pw.println("1st statement");
            pw.println("2nd statement");
            //pw.flush();

I attached my pw to the console output.This code will not print the output to the screen because pw.flush() is not invoked(commented as you see).If you uncomment it,you'll see the output on the screen becuase it "flushes" its buffer and sends the data to the output stream which is the console output here.

Cheers