IO Output Test

output

$ javac TestIO.java && java TestIO > out.txt
1783293664
raw System.out.println: 26941490983
raw System.out.print: 12888388868
PrintWriter(System.out): 867392610

TestIO.java

import java.io.*;

public class TestIO {
  public static void testSystemOutPrintln() {
    for (int i = 0; i < 10_000_000; i++) {
      System.out.println(i);
    }
  }
  public static void testSystemOutPrint() {
    for (int i = 0; i < 10_000_000; i++) {
      System.out.print(i+"\n");
    }
  }
  public static void testPrintWriter() {
    PrintWriter out = new PrintWriter(System.out);
    for (int i = 0; i < 10_000_000; i++) {
      out.println(i);
    }
    out.flush();
  }

  public static void main(String[] args) {
    int out = 0;
    // Warm-up
    for (int i = 0; i < 1_000_000; i++) {
      out += i;
    }
    System.err.println(out);
    long t1, t2;

    System.gc();
    t1 = System.nanoTime();
    testSystemOutPrintln();
    t2 = System.nanoTime();
    System.err.printf("raw System.out.println: %d\n",t2-t1);

    System.gc();
    t1 = System.nanoTime();
    testSystemOutPrint();
    t2 = System.nanoTime();
    System.err.printf("raw System.out.print: %d\n",t2-t1);

    System.gc();
    t1 = System.nanoTime();
    testPrintWriter();
    t2 = System.nanoTime();
    System.err.printf("PrintWriter(System.out): %d\n",t2-t1);
  }
}