benchmark and the cause for difference between c# and java
benchmarking, c#, io, java, visual-studio
Solution
For one thing: in Java you're using the platform's default encoding. That may well be a fixed "single byte per character" encoding, which is clearly going to be simpler than using UTF-8, which .NET does by default.
In addition, you're writing two newlines in .NET, and only one in Java.
One thing to check is whether you're CPU-bound or IO-bound. I'd expect this to be IO-bound, but I've certainly been surprised before now.
Finally, you should run each test after a reboot to try to remove disk caches from the equation as far as possible.
Problem
I have a puzzling situation and I would need an expert opinion as to the cause of the phenomenon explained below. A couple of weeks ago, I have conducted a session titled "An overview .NET for Java developers" and as a part of it I wrote a quick class C# (3.5 framework) to read from a file and write to another file line by line (in an iteration). As my audience were java developers, I had the same code in a java class for side by side comparison. However, when I ran these classes on the same machine, to my surprise the java code consistently ran twice as fast than C# code. I have tried many optimizations in C# code to narrow the gap but could not succeed. There has to be an explanation and I am looking for somebody that can explain the cause. I am attaching the source code from both the classes for your reference. Java class ``` public class ReadWriteTextFile { static public String getContents(File aFile, String OutPutFileName) { StringBuilder contents = new StringBuilder(); try { BufferedReader input = new BufferedReader(new FileReader(aFile)); FileReader x = new FileReader(aFile); try { String line = null; while (( line = input.readLine()) != null){ setContents(OutPutFileName, line + System.getProperty("line.separator")); } } finally { input.close(); } } catch (IOException ex){ ex.printStackTrace(); } return contents.toString(); } static public void setContents(String FileName, String aContents) throws FileNotFoundException, IOException { try { FileWriter fstream = new FileWriter(FileName, true); BufferedWriter out = new BufferedWriter(fstream); out.write(aContents); out.close(); } catch (Exception xe) { xe.printStackTrace(); } } public static void main (String[] aArguments) throws IOException { System.out.println(getDateTime() + ": Started"); File testFile = new File("C:\\temp\\blah.txt"); String testFile2 = "C:\\temp\\blahblah.txt"; for(int i=0; i<100; i++){ getContents(testFile, testFile2); } System.out.println(getDateTime() + ": Ended"); } private synchronized static String getDateTime() { DateFormat dateFormat = new SimpleDateFormat( "yyyy/MM/dd HH:mm:ss"); Date date = new Date(); return dateFormat.format(date); } } ``` C# class ``` class ReadWriteTextFile { static void Main(string[] args) { System.Diagnostics.Trace.WriteLine(getDateTime() + ": Started"); String testFile = "C:\\temp\\blah.txt"; String testFile2 = "C:\\temp\\blahblah.txt"; for(int i=0; i<100; i++){ getContents(testFile, testFile2); } System.Diagnostics.Trace.WriteLine(getDateTime() + ": Ended"); } static public void getContents(String sourceFile, String targetFile) { try { using (StreamReader r = File.OpenText(sourceFile)) { String line; while ((line = r.ReadLine()) != null) { setContents(targetFile, line); } r.Close(); } } catch (IOException ex){ Console.WriteLine(ex.StackTrace); } } static public void setContents(String targetFile, String aContents) { try { //FileStream fsO = new FileStream(targetFile, FileMode.Append); //StreamWriter w = new StreamWriter(fsO); FileStream fs = new FileStream(targetFile, FileMode.Append, FileAccess.Write, FileShare.None); using (StreamWriter w = new StreamWriter(fs)) { w.WriteLine(aContents + "\n"); } } catch (Exception xe) { Console.WriteLine(xe.StackTrace); } } private static String getDateTime() { DateTime dt = DateTime.Now; return dt.ToString("yyyy/MM/dd HH:mm:ss"); } } ```