Java Concurrency (&c)

I should probably comment on this paper from my colleague Robert Hundt , where he writes the same benchmark in Java, Scala, Go, Python and C++ ( TL;DR here ). Short version: Initially, C++ was faster than Scala, and Scala was faster than Java. I volunteered to make some improvements, which ended up with the C++ and Java implementations being about the same speed. Some C++ hackers then went and improved the C++ benchmark by another ~6x, and I didn't think I should go down that road. Imagine my surprise when I got this email from a friend of mine this morning: Date: Fri, 3 Jun 2011 03:20:48 -0700 Subject: Java Tunings To: Jeremy "Note that Jeremy deliberately refused to optimize the code further, many of the C++ optimizations would apply to the Java version as well." Slacker. Gee, thanks for making me look good, Robert. (Actually, I had approved that language, but I didn't realize anyone would actually read the paper. :) ) Anyway, I was not just being obdurate here;...

Josh Bloch and I gave one of his Java Puzzlers talk at Google I/O this year. If you hate Java, you can waste a perfectly good hour listening to us make unfunny jokes at its expense.

I recently got a note on another blog post asking this question: I have a general question on the thread safety and this is not directly related with your blog. I would appreciate if you could post it on your blog. I have a class that has only one static method that accepts two string parameters and does some operation locally (as shown below). Do I need to synchronize this method? public class A {   public static boolean getDate(String str, String str2){     SimpleDateFormat formatter =       new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");     boolean isBefore = false;     Date date1;     Date date2;     try {       date1 = formatter.parse(str);       date2 = formatter.parse(str);       isBefore = date1.after(date2);     } catch (Exception...

Today, I'll discuss a little tweak I made to java.util.Logging that made my logging throughput double. I want to use it as an illustration that it often isn't very difficult to improve the performance of concurrent code by doing things that are actually pretty easy to do. So, "I" have an application that is running a couple of hundred threads on an 8-core machine, and it wants to log about 2MB a second using java.util.Logger . When I say "I have", I actually mean "someone else has", because if "I" had to log a megabyte a second, there is no way I would use java.util.Logger to do it. Still, we all make our choices. When I came to this code, it was already doing sensible things like buffering its output. It wasn't doing something more complicated, like using a dedicated logging thread. It could log about 1MB a second, and was chewing through CPU pretty rapidly. I just decided to run our profiler on the code and see where the bot...