System.out.println vs PrintWriter performance comparison?

Question

I want to print 1 million lines to stdout.

System.out.println(result);

Or

PrintWriter out = new PrintWriter(System.out);
out.println(result);
out.flush();

To get better performance(speed wise), which one should I use and why?

--Edit-- How about BufferedWriter?

Answer 1

PrintWritter gives better performance, though the time difference is not quite visible in smaller programs. But becomes quite apparent as the number of lines to be printed increases.

I used the execution time of these snippets for the test. System.out.println(i)

class Sprint{
    public static void main(String[] args) {
        int n=10000000;
        for(int i=0;i<n;i++){
            System.out.println(i);
        }
    }
}

out.println(i);

import java.io.*;
class Pprint{
    public static void main(String[] args) {
        PrintWriter out = new PrintWriter(System.out);
        int n=10000000;
        for(int i=0;i<n;i++){
            out.println(i);
        }
        out.flush();
    }
}

I used n=10 to 10^7 and executed both of them 3 times for each n. There was a visible difference in performance after the value of n exceeds 10^3.

Answer 2

Wrapping System.out in a different output stream won't really make a difference. It will just call the same methods. Your limitations are creating millions of small objects and the console's ability to receive, hold and display everything.

Also, designing a simple test is easy.

public static void main(String[] args) {
    System.out.println();
    long start = 0L;

    start = System.currentTimeMillis();

    for(int i = 0; i <= 999999; i++)
        System.out.println(i);

    long printStreamTime = System.currentTimeMillis() - start;

    PrintWriter writer = new PrintWriter(System.out);

    System.gc();
    try {
        Thread.sleep(1000L);
    } catch(InterruptedException ie) {}

    start = System.currentTimeMillis();

    for(int i = 0; i <= 999999; i++)
        writer.println(i);

    long printWriterTime = System.currentTimeMillis() - start;

    System.out.println();

    System.out.println("PrintStream time = " + (printStreamTime / 1000.0));
    System.out.println("PrintWriter time = " + (printWriterTime / 1000.0));
}

I got ~49 seconds for both. Almost identical.

If you want speed, write to a file and open it.

Answer 3

My suggestion is to use PrintWriter for better time performance, though the time difference is not major in smaller programs. For larger programs you may notice significant difference. I have replaced and run System.out.println with PrintWriter and my execution time reduced from 0.06 sec to 0.05 sec.

Here is a link to a similar question: https://discuss.codechef.com/questions/62586/systemoutprintln-vs-printwriter

Hope it helps :)