A benchmark for how quickly random numbers can be written to file in Java

BenchmarkRandomNumberWriting.java

import java.util.Random;
import java.io.FileWriter;
import java.io.IOException;

class BenchmarkRandomNumberWriting {
  public static void main(String[] args) {
    if (args.length != 2) {
      System.err.println("Incorrect number of arguments!");
      System.err.println(
        "Usage: java BenchmarkRandomNumberGenerator <output file> <line count>");
      System.exit(1);
    }

    // setup our file writer
    FileWriter fw = null;
    try {
      fw = new FileWriter(args[0]);
    } catch (IOException e) {
      System.err.println("Failed to open " + args[0]);
      System.err.println("Error: " + e.getMessage());
      System.exit(2);
    }

    // check how many lines of output we should write
    int count = 0;
    try {
      count = Integer.parseInt(args[1]);
    } catch (NumberFormatException e) {
      System.err.println(args[1] + " must be an integer");
      System.exit(3);
    }

    // get the proper line-endings for the platform
    // \n on Linux, \r\n on Windows
    String lineSeperator = System.getProperty("line.separator");

    // run our random number generator
    Random rng = new Random();
    long startTime = System.nanoTime();
    try {
      for (int i = 0; i < count; ++i) {
        fw.write(Integer.toString(rng.nextInt()) + lineSeperator);
      }
      fw.close();
    } catch (IOException e) {
      System.err.println("Failed to write to " + args[0]);
      System.err.println("Error: " + e.getMessage());
      System.exit(2);
    }

    // print out how long it took
    long endTime = System.nanoTime();
    double elapsed = (endTime - startTime) / 1e9;
    System.out.println(elapsed);
  }
};