[ajug-members] asked a different way

[Steve Finch]

Micro-benchmarks are almost impossible to do in Java.  Brian Goetz
addressed this in articles and in "Java Concurrency in Practice"

http://www.ibm.com/developerworks/java/library/j-jtp02225.html

If you really want to know what's going on, as Mike said, use JConsole.
If you are using Java 5, there's some cmd line parameters to add.

http://java.sun.com/developer/technicalArticles/J2SE/jconsole.html

-----Original Message-----
From: Wilson, Jeff [mailto:jw9615 at att.com] 
Sent: Friday, September 12, 2008 8:45 AM
To: ajug-members at ajug.org; Burr Sutter
Subject: Re: [ajug-members] asked a different way

If I'm reading your program correctly, you aren't actually allocating
any objects. The statement:

Rational fraction;

Allocates only enough memory to hold a reference -- its essentially a
pointer, so it probably is on the order of 4 bytes. It doesn't actually
allocate an object.

Try changing it to:

Rational fraction = new Rational();

And see what happens. However, even that is not guaranteed to allocate
any memory because the VM can optimize this allocation away since the
object is never used.

A more interesting test might be to do the following:

List<Rational> fractions = new ArrayList<Rational>();
for (int I = 0; i< 100; i++) {
  fractions.add(new Rational());
  println(runtime.freeMemory());
}
fractions.empty();
println(runtime.freeMemory());

+jeff (MJW)
---

"If you are going through hell, keep going."
 -W. Churchill 

---------------------------------------------
M. Jeff Wilson, Lead Member Technical Staff
AT&T Services, Inc.
Operations & Service Dev
jw9615 at att.com 
+1 404.499.7235
-----Original Message-----
From: mcdaniel [mailto:521 at ofig.org] 
Sent: Thursday, September 11, 2008 5:45 AM
To: Burr Sutter; ajug-members at ajug.org
Subject: [ajug-members] asked a different way

why does this post/attached not show up on the ajug user/mail group?

thanks

barclay
 >>>>>>>>>>>>>>

let me ask this then, how can i display the amt of free-memory
before/after 10000 Rational objects are allocated, then not saved in a
variable- which makes them garbage? per (near how) the *attached*
screen-shot (fails to show)

barclay



barclay

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