#159 Fix overkilled garbage collection on static fields

[Flemming N. Larsen]

jprudent (jerp2) proposes a better fix for Bug-244 regarding overkilled garbage collection on static fields on robots. His comment can be read here.

I really like his suggestion:
"To fix this more properly, I wouldn't clean any of the class loaded by a parent classloader. In my case, clojure.jar is added in classpath and any related classes is loaded via the Container classloader."

This is the way it should be fixed so Clojure and other languages as well will be supported by Robocode. :-)

[Flemming N. Larsen]

I have created an 1.9.2.4 Alpha version of Robocode here with a possible fix.

Please try it out and check if this fixes the issue with Clojure.

[jerp2]

Hi,

I've tried. It successfully load the first round now !!!

... but ... on the second round, hitting the Restart button, I get NullPointerException. I didn't have time to find why, but I would bet it's the cleaning. Here is my guess: the sorting between robot classes and system classes is perfectly done so clojure classes don't get clean up. Still, the rebot generated with clojure has some static fields that get clean up, hence the NPE.

But, I think the fix is fine for Scala, must try this out !

I'll give a deeper look this weekend to know exactly what is happening.

Thanks :)

[Flemming N. Larsen]

You are welcome.

If you have a jar file or the classes for the robot(s). Or the sources + a short description of how to compile your robots for testing this change, you are welcome to send it to me or attach it here. Then I will try to find out, what is going on inside Robocode since it causes problems with rounds two.

[jerp2]

Hi,

Here is my repo : https://github.com/jprudent/clobocode

The bots are doing almost nothing, except gearing radar and gun when round
starts.

There is a Readme that explains how to build. The generated jar is loadable
in Robocode.

Here is the jars :
https://drive.google.com/file/d/0B9LaCjHSfccCSXZUbE1kQkpJLUE/view?usp=sharing

Thanks :)

On Sat, Oct 11, 2014 at 4:13 AM, Flemming N. Larsen fnl@users.sf.net
wrote:

You are welcome.

If you have a jar file or the classes for the robot(s). Or the sources + a
short description of how to compile your robots for testing this change,
you are welcome to send it to me or attach it here. Then I will try to find
out, what is going on inside Robocode since it causes problems with rounds
two.

---

• [feature-requests:#159]
  http://sourceforge.net/p/robocode/feature-requests/159 Fix overkilled
  garbage collection on static fields*

Status: open
Group: Future Release
Labels: static field GC Clojure
Created: Sun Oct 05, 2014 08:02 PM UTC by Flemming N. Larsen
Last Updated: Fri Oct 10, 2014 05:45 AM UTC
Owner: Flemming N. Larsen

jprudent (jerp2) proposes a better fix for Bug-244
https://sourceforge.net/p/robocode/bugs/244 regarding overkilled
garbage collection on static fields on robots. His comment can be read
here https://sourceforge.net/p/robocode/bugs/244/?limit=10&page=1#68bd.

I really like his suggestion:
"To fix this more properly, I wouldn't clean any of the class loaded by a
parent classloader. In my case, clojure.jar is added in classpath and any
related classes is loaded via the Container classloader."

This is the way it should be fixed so Clojure and other languages as well
will be supported by Robocode. :-)

---

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https://sourceforge.net/p/robocode/feature-requests/159/

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--
(Jérôme Prudent)

[Flemming N. Larsen]

Thank you for sending the zipped jar file. I use the clojure-1.5.1.jar which I have added to the classpath of the JVM that runs Robocode and also disabled security (-DNOSECURITY=true).

You are right. Your robots seems to work with the first round, and I also get a NPE from the robots, with the 2nd round.

I will dig into this and figure out what goes wrong. Please don't get impatient with me, as I might first get time for it in the end of the weekend. Let's see. :-)

[jerp2]

Hi,

You know I am not in a hurry AT ALL. Take your time. I lack some free time
myself ;)

On Tue, Oct 14, 2014 at 11:45 PM, Flemming N. Larsen fnl@users.sf.net
wrote:

Thank you for sending the zipped jar file. I use the clojure-1.5.1.jar
http://www.java2s.com/Code/JarDownload/clojure/clojure-1.5.1.jar.zip
which I have added to the classpath of the JVM that runs Robocode and also
disabled security (-DNOSECURITY=true).

You are right. Your robots seems to work with the first round, and I also
get a NPE from the robots, with the 2nd round.

I will dig into this and figure out what goes wrong. Please don't get
impatient with me, as I might first get time for it in the end of the
weekend. Let's see. :-)

---

• [feature-requests:#159]
  http://sourceforge.net/p/robocode/feature-requests/159 Fix overkilled
  garbage collection on static fields*

Status: open
Group: Future Release
Labels: static field GC Clojure
Created: Sun Oct 05, 2014 08:02 PM UTC by Flemming N. Larsen
Last Updated: Fri Oct 10, 2014 08:13 PM UTC
Owner: Flemming N. Larsen

jprudent (jerp2) proposes a better fix for Bug-244
https://sourceforge.net/p/robocode/bugs/244 regarding overkilled
garbage collection on static fields on robots. His comment can be read
here https://sourceforge.net/p/robocode/bugs/244/?limit=10&page=1#68bd.

I really like his suggestion:
"To fix this more properly, I wouldn't clean any of the class loaded by a
parent classloader. In my case, clojure.jar is added in classpath and any
related classes is loaded via the Container classloader."

This is the way it should be fixed so Clojure and other languages as well
will be supported by Robocode. :-)

---

Sent from sourceforge.net because you indicated interest in
https://sourceforge.net/p/robocode/feature-requests/159/

To unsubscribe from further messages, please visit
https://sourceforge.net/auth/subscriptions/

--
(Jérôme Prudent)

[Flemming N. Larsen]

Hi again,
I have made a new Alpha-2 version here:
http://robocode.sourceforge.net/files/robocode-1.9.2.4-Alpha-2-setup.jar

This version works for me with your robots. :-)

[Flemming N. Larsen]

Closed as this has been implemented in 1.9.2.4