Volatile vs synchronized

Question

Does anyone have any opinions or references on the performance advantage (or disadvantage) of using a volatile variable as opposed to synchronizing on some object to reference it?

Answer 1

Here's a little code snippet I dreamed up and the results
public class Test {
     static volatile int thisInt = 0;
     static int thatInt = 0;
     static int theirInt = 0;
     public static void testVolatile() {
          long startTime = System.currentTimeMillis();
          for (int i = 0; i < 100000000; i++)
               thisInt = i;
          long stopTime = System.currentTimeMillis();
          System.out.println("Total time for volatile: " + (stopTime - startTime));
     public static synchronized void testSynchronized() {
          long startTime = System.currentTimeMillis();
          for (int i = 0; i < 100000000; i++)
               thatInt = i;
          long stopTime = System.currentTimeMillis();
          System.out.println("Total time for synchronized: " + (stopTime - startTime));
     public static void testFineSynchronized() {
          long startTime = System.currentTimeMillis();
          for (int i = 0; i < 100000000; i++) {
               synchronized (Test.class) {
                    theirInt = i;
          long stopTime = System.currentTimeMillis();
          System.out.println("Total time for fine synchronized: " + (stopTime - startTime));
     public static void main(String args[]) {
          Test.testVolatile();
          Test.testSynchronized();
          Test.testFineSynchronized();
}java version "1.3.1"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1-b24)
Java HotSpot(TM) Client VM (build 1.3.1-b24, mixed mode)
The computer is a single processor PII 400Mhz
Total time for volatile: 1332
Total time for synchronized: 1572
Total time for fine synchronized: 95107