Java speed vs. C++.

[Mike Cox]

Hi. I recently ran a benchmark against two simple programs, one written in
Java and the other in C++. The both accomplish the same thing, outputting
"Hello World" on my screen. The C++ program took .5 seconds to complete on
my 400 Mhz PC while the Java program took 6.5 seconds.

I am running the SUSE 8.2 Linux distribution.

Why is Java that much slower than the C++ program? I read on Slashdot that
Java was almost as fast as C++. Here are my programs:

test.cpp

#include <iostream>
using namespace std;
int main()
{
cout<<"Hello World";
}
test.java

public class test
{
public static void main(String[] args)
{
System.out.prin tln("Hello world");
}
}

The reason I ask is because I'm thinking of using Apache and Jakarta to do
some development. If Java cannot be speeded up, I will be forced to find
another alternative.

[Siemel Naran]

"Mike Cox" <mi**********@y ahoo.com> wrote in message

Hi. I recently ran a benchmark against two simple programs, one written in Java and the other in C++. The both accomplish the same thing, outputting
"Hello World" on my screen. The C++ program took .5 seconds to complete on my 400 Mhz PC while the Java program took 6.5 seconds.

I am running the SUSE 8.2 Linux distribution.

Why is Java that much slower than the C++ program? I read on Slashdot that Java was almost as fast as C++. Here are my programs:

test.cpp

#include <iostream>
using namespace std;
int main()
{
cout<<"Hello World";
}
test.java

public class test
{
public static void main(String[] args)
{
System.out.prin tln("Hello world");
}
}

The reason I ask is because I'm thinking of using Apache and Jakarta to do
some development. If Java cannot be speeded up, I will be forced to find
another alternative.

Maybe it takes time to start up the Java engine, so it will appear to be
much slower for a very short program. Try a lenghthier test. Also, the
Java implementation makes a difference too.

[Mike Cox]

Siemel Naran wrote:

Maybe it takes time to start up the Java engine, so it will appear to be
much slower for a very short program. Try a lenghthier test. Also, the
Java implementation makes a difference too.

Would that be a concern when I use Jakarta to run a web application? Or
does Jakarta start up and never shut down the engine?

[Ann]

"Siemel Naran" <Si*********@RE MOVE.att.net> wrote in message
news:X4******** ***********@bgt nsc05-news.ops.worldn et.att.net...

"Mike Cox" <mi**********@y ahoo.com> wrote in message

Hi. I recently ran a benchmark against two simple programs, one written

in

Java and the other in C++. The both accomplish the same thing, outputting "Hello World" on my screen. The C++ program took .5 seconds to complete

on

my 400 Mhz PC while the Java program took 6.5 seconds.

I am running the SUSE 8.2 Linux distribution.

Why is Java that much slower than the C++ program? I read on Slashdot

that

Java was almost as fast as C++. Here are my programs:

On my machine (WIN XP) it takes at least 5 seconds to start
any program from a dos window that is not built into COMMAND.COM

[Ann]

The reason I ask is because I'm thinking of using Apache and Jakarta to do
some development. If Java cannot be speeded up, I will be forced to find
another alternative.

Visual Basic is supported, I tried a "hello world" type program and it
took less than a second including the time to create the window.

[Arijit]

Ann wrote:

On my machine (WIN XP) it takes at least 5 seconds to start
any program from a dos window that is not built into COMMAND.COM

Off topic, but Win XP doesn't even have command.com :)

[Ann]

"Arijit" <pa*****@yahoo. co.in> wrote in message
news:31******** *****@individua l.net...

Ann wrote:

On my machine (WIN XP) it takes at least 5 seconds to start
any program from a dos window that is not built into COMMAND.COM

Off topic, but Win XP doesn't even have command.com :)

--------- ya does ---------------
Volume in drive C has no label.
Volume Serial Number is 502A-848E

Directory of C:\WINDOWS\SYST EM32

08/29/2002 04:00 AM 50,620 COMMAND.COM
1 File(s) 50,620 bytes
0 Dir(s) 16,377,466,880 bytes free

[E. Robert Tisdale]

Mike Cox wrote:

I recently ran a benchmark against two simple programs, one written in
Java and the other in C++. The both accomplish the same thing, outputting
"Hello World" on my screen. The C++ program took .5 seconds to complete on
my 400 Mhz PC while the Java program took 6.5 seconds.

I am running the SUSE 8.2 Linux distribution. Why is Java that much slower than the C++ program?
Java programs are almost always almost as fast as C++ programs.
The problem with Java
(and other interpreted languages such as BASIC and MATLB)
is that it doesn't (can't) optimize certain [fine grain] operations
very well even if you compile the byte code into machine code.
This is very well documented in numerical programming.
I used Google

http://www.google.com/

to search for

+"Java numerical programming"

and I found lots of stuff.

The bottom line is
You should *not* be afraid to write applications --
even high performance numerical applications --
in Java but be aware that you might run into difficulties
that you just can't work around without calling a routine
written in some other language such as C++.
I read on Slashdot that Java was almost [always] as fast as C++.
Here are my programs: cat test.cpp #include <iostream>
int main(int argc, char* argv[]) {
std::cout << "Hello World" << std::endl;
return 0;
}
g++ -Wall -ansi -pedantic -o test test.cpp
g++ --version g++ (GCC) 3.4.1 time ./test Hello World
0.003u 0.005s 0:00.00 0.0% 0+0k 0+0io 0pf+0w cat test.java public class test {
public static void main(String[] args) {
System.out.prin tln("Hello world");
}
}
javac test.java
which javac /usr/java/j2sdk1.4.2_05/bin/javac time java test Hello world
0.271u 0.042s 0:00.32 96.8% 0+0k 0+0io 1pf+0w cat /etc/fedora-release

Fedora Core release 2 (Tettnang)

[Chris Uppal]

Mike Cox wrote:

Would that be a concern when I use Jakarta to run a web application? Or
does Jakarta start up and never shut down the engine?

The startup time is only an issue for applications that either need to start
really fast or which only run for a short time (like your example). For any
reasonably long running program, the startup time is essentially irrelevant
(however irritating while debugging).

One thing to beware of, though, when considering Java in a server environment,
is that the startup time makes Java a very poor choice for writing pure CGI
programs. (But then I don't think CGI is such a wonderful idea anyway...)

Incidentally, the latest Sun JVM has some tweaks to reduce the minimum startup
time. I find them quite effective.

-- chris

[KiLVaiDeN]

"Mike Cox" <mi**********@y ahoo.com> wrote in message
news:31******** *****@individua l.net...

Hi. I recently ran a benchmark against two simple programs, one written
in
Java and the other in C++. The both accomplish the same thing, outputting
"Hello World" on my screen. The C++ program took .5 seconds to complete
on
my 400 Mhz PC while the Java program took 6.5 seconds.

I am running the SUSE 8.2 Linux distribution.

Why is Java that much slower than the C++ program? I read on Slashdot
that
Java was almost as fast as C++. Here are my programs:

test.cpp

#include <iostream>
using namespace std;
int main()
{
cout<<"Hello World";
}
test.java

public class test
{
public static void main(String[] args)
{
System.out.prin tln("Hello world");
}
}

The reason I ask is because I'm thinking of using Apache and Jakarta to do
some development. If Java cannot be speeded up, I will be forced to find
another alternative.

Java takes time to initialise things, like preloading the classes, and lot
of other things. It's also an interpreted language, and it will be always
slower than compiled programs, no matter what you do. There is
native-compilers available if it really is a problem, and through JNI, you
can run native compiled code, if the need of speed is relevant.

But knowing those things, once running, a Java program, or at least a
consequent Java program which can be used for benchmarking purposes, can
compare in speed with C++ ones. The Jvm has had several optimisations that
made it quite good performance-wise to interpret Java code.

K