Shaun

Tried a few tests myself, and with a few tweaks, the results end up being a lot closer:
1. modify your test so that there is some activity within the loop (just instantiating an empty String)
2. Run your test loop multiple times and discard the timings of the first few runs – whenever we run performance tests for a production webapp we always give the JVM a chance to ‘warm up’ before starting the test statistics, thereby giving the JVM a chance to work its internal optimzation magic.
3. Run with a 1.6 rather than a 1.5 JVM (I note that you’re already doing this, but initially I wasn’t and it made a massive impact to the Groovy timings). This gave about a 50x perf boost to the Groovy test for me!

Now running the tests, the Java version took ~30ms and the Groovy version took ~70ms

For the record, here are the Groovy and Java versions I’m using
monaco:Temp james$ groovy -version
Groovy Version: 1.6.4 JVM: 1.6.0_13
monaco:Temp james$ java -version
java version “1.6.0_13″
Java(TM) SE Runtime Environment (build 1.6.0_13-b03-211)
Java HotSpot(TM) 64-Bit Server VM (build 11.3-b02-83, mixed mode)

… and here are the modified test files

for (outer in 1..20){

long max = 1000000;
long start = Calendar.getInstance().getTimeInMillis();
for(int i=0;i<max; i++) {
String s=new String();
}
long end = Calendar.getInstance().getTimeInMillis();
long duration = end – start;
println(duration);

}

… and Java…

import java.util.*;
public class Test{

public static void main(String[] args){
for (int outer=1; outer<20; outer++){

long max = 1000000;
long start = Calendar.getInstance().getTimeInMillis();
for(int i=0;i<max; i++) {
String s=new String();
}
//for (i in 1..max){}
long end = Calendar.getInstance().getTimeInMillis();
long duration = end – start;
System.out.println(duration);
}
}
}