Java - System.out effect on performance

Question

I\'ve seen this question and it\'s somewhat similar. I would like to know if it really is a big factor that would affect the performance of my application. Here\'s my scenar

Answer 1

I was recently testing with (reading and) writing large (1-1.5gb) text-files, and I found out that:

PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(java.io.FileDescriptor.out), "UTF-8"), 512));
out.println(yourString);
//...
out.flush();

is in fact almost 250% faster than

System.out.println(yourString);

My test-program first read about 1gb of data, processed it a bit and outputted it in slightly different format.

Test results (on Macbook Pro, with SSD reading&writing using same disk):

• data-output-to-system-out > output.txt => 1min32sec
• data-written-to-file-in-java => 37sec
• data-written-to-buffered-writer-stdout > output.txt => 36sec

I did try with multiple buffer sized between 256-10k but that didn't seem to matter.

So keep in mind if you're creating unix command-line tools with Java where output is meant to be directed or piped to somewhere else, don't use System.out directly!