Re: [collections] LRUMap Problem ConcurrentModificationException
Hi,
I'm using the one from the map package my import looks like this:
import org.apache.commons.collections.map.LRUMap;
As I've seen the LRUMap outside the map package is deprecated.
René
2009/6/15 Leon Rosenberg rosenberg.l...@googlemail.com:
weird enough there are two LRUMap classes in commons collections,
org.apache.commons.collections and org.apache.commons.collections.map.
Which one are you using?
regards
Leon
On Mon, Jun 15, 2009 at 6:00 PM, Renè Glanzerrene.glan...@gmail.com wrote:
Yes of course,
the code with the time based cache systems was set up with an ordniary
HashMap. But when rapidly seach requests are
generated the time based mechanism fails to delete old entries - cause
they are not old enough - and so the cache will
raise up until the entire VM memory is used. Then i found the LRUMap
switched to it and bang Exception in my delete method.
When i switch back to HashMap the code runs well - as currently on the
productive system - except the open memory leak.
René
2009/6/15 Leon Rosenberg rosenberg.l...@googlemail.com:
just out of curiosity have you tried the same code with a standard hashmap?
Leon
On Mon, Jun 15, 2009 at 4:37 PM, Renè Glanzerrene.glan...@gmail.com wrote:
Hello,
side note accepted :-)
In my class I checked the get, put and remove methods. All are
synchronized.
As you can see also the code which wants to delete the elements is
synchronized.
So I've no clue where the ConcurrentModificationException is comming
from :-(
Thanks René
2009/6/15 Leon Rosenberg rosenberg.l...@googlemail.com:
Hello,
on a side note, generics make reading of code easier :-)
you haven't posted the whole code, but have you (double)checked that
all other acesses to store are synchronized?
regards
Leon
On Mon, Jun 15, 2009 at 2:31 PM, Renè Glanzerrene.glan...@gmail.com
wrote:
I'm calling the remove() method on the iterator. I know when i call
the remove on the map itself it will cause the problem with my
currently running iterator, but i'm aware of that.
Here is the code block which should delete old entries:
store: is the LRUMap
birth: is a long which keeps the creation time when this is set to 0
the item should be deleted
public void removeAllExpiredItems()
{
synchronized(this.store)
{
Iterator it=this.store.keySet().iterator();
while(it.hasNext())
{
Object key=it.next();
Object o=this.get(key);
if(o != null)
{
Item iEntry=(Item)this.store.get(key);
if(iEntry.birth==0)
it.remove(); //Here the exception occurs
}
}
this.setLastCleanDate(new Date()); //only to know when the
deleter run the last time
}
}
Thanks for any help :-)
René
2009/6/15 James Carman ja...@carmanconsulting.com:
Are you calling remove() on the iterator or on the map itself?
On Mon, Jun 15, 2009 at 6:37 AM, Renè Glanzerrene.glan...@gmail.com
wrote:
Hello,
is there still no help for me?
Is somebody able to explain me, why i get this
java.util.ConcurrentModificationException
on iterating and calling remove() on the LRUMap?
Please
René
2009/6/10 Renè Glanzer rene.glan...@gmail.com:
Hello Ted,
thanks for the fast response. I understand that simultaneously puts
and gets do not cause the exception cause they are synchronized in my
class.
And my stated code-fragment is the part which wants to delete the
entries from the underlying LRUMap. And my code is wrapped in the
synchronized block. But i think the LRUMap herselfe also iterates the
entries and this maybe happens at the same time when my iterator is
checking and trying to delete elements. My class is not implementing
the LRUMap but has one LRUMap as a variable.
So your solution to override the removeLRU(Entry) methode would not
help meunfortunatelly :-(
For now i really do not know how to solve the problem in an easy way
without refractoring the entire code?
Any other solutions?
Thanks René
2009/6/9 Ted Dunning ted.dunn...@gmail.com:
I apologize for not reading your thread with great care, but I think
that
your problem is pretty clear.
The issue is not to do with gets and puts overlapping. The issue is
that a
put or remove happened during the life of your iterator.
One way to avoid this is to synchronize the entire method that does
the
deletion of old elements. To speed that up, you might just
synchronize the
scan for elements to delete and collect them into a list. Then you
can
delete them outside the loop. Since your scan is probably pretty
fast, this
may be sufficient. With very high levels of updates and threading,
it would
cause problems.
Another option is to clone the table. I believe that some
implementations
of LRUMap in Lucene do copy-on-write semantics, but I don't think
that
collections has these. Without that, cloning will be as slow or
slower than
your scan so the first option would be better.
I am curious,
Re: [collections] LRUMap Problem ConcurrentModificationException
Hey Otis,
i found this one:
https://issues.apache.org/jira/browse/COLLECTIONS-3
but there is no solutions only an assumption at the end of the thread??
René
2009/6/15 Otis Gospodnetic otis_gospodne...@yahoo.com:
Btw. I think you'll find a report about this from a few years ago in the
Collections JIRA. Just search for my name.
Otis
--
Sematext -- http://sematext.com/ -- Lucene - Solr - Nutch
- Original Message
From: Renè Glanzer rene.glan...@gmail.com
To: Commons Users List user@commons.apache.org
Sent: Monday, June 15, 2009 12:00:54 PM
Subject: Re: [collections] LRUMap Problem ConcurrentModificationException
Yes of course,
the code with the time based cache systems was set up with an ordniary
HashMap. But when rapidly seach requests are
generated the time based mechanism fails to delete old entries - cause
they are not old enough - and so the cache will
raise up until the entire VM memory is used. Then i found the LRUMap
switched to it and bang Exception in my delete method.
When i switch back to HashMap the code runs well - as currently on the
productive system - except the open memory leak.
René
2009/6/15 Leon Rosenberg :
just out of curiosity have you tried the same code with a standard hashmap?
Leon
On Mon, Jun 15, 2009 at 4:37 PM, Renè Glanzerwrote:
Hello,
side note accepted :-)
In my class I checked the get, put and remove methods. All are
synchronized.
As you can see also the code which wants to delete the elements is
synchronized.
So I've no clue where the ConcurrentModificationException is comming
from
:-(
Thanks René
2009/6/15 Leon Rosenberg :
Hello,
on a side note, generics make reading of code easier :-)
you haven't posted the whole code, but have you (double)checked that
all other acesses to store are synchronized?
regards
Leon
On Mon, Jun 15, 2009 at 2:31 PM, Renè Glanzerwrote:
I'm calling the remove() method on the iterator. I know when i call
the remove on the map itself it will cause the problem with my
currently running iterator, but i'm aware of that.
Here is the code block which should delete old entries:
store: is the LRUMap
birth: is a long which keeps the creation time when this is set to 0
the item should be deleted
public void removeAllExpiredItems()
{
synchronized(this.store)
{
Iterator it=this.store.keySet().iterator();
while(it.hasNext())
{
Object key=it.next();
Object o=this.get(key);
if(o != null)
{
Item iEntry=(Item)this.store.get(key);
if(iEntry.birth==0)
it.remove(); //Here the exception occurs
}
}
this.setLastCleanDate(new Date()); //only to know when the
deleter run the last time
}
}
Thanks for any help :-)
René
2009/6/15 James Carman :
Are you calling remove() on the iterator or on the map itself?
On Mon, Jun 15, 2009 at 6:37 AM, Renè Glanzer
wrote:
Hello,
is there still no help for me?
Is somebody able to explain me, why i get this
java.util.ConcurrentModificationException
on iterating and calling remove() on the LRUMap?
Please
René
2009/6/10 Renè Glanzer :
Hello Ted,
thanks for the fast response. I understand that simultaneously puts
and gets do not cause the exception cause they are synchronized in my
class.
And my stated code-fragment is the part which wants to delete the
entries from the underlying LRUMap. And my code is wrapped in the
synchronized block. But i think the LRUMap herselfe also iterates the
entries and this maybe happens at the same time when my iterator is
checking and trying to delete elements. My class is not implementing
the LRUMap but has one LRUMap as a variable.
So your solution to override the removeLRU(Entry) methode would not
help meunfortunatelly :-(
For now i really do not know how to solve the problem in an easy way
without refractoring the entire code?
Any other solutions?
Thanks René
2009/6/9 Ted Dunning :
I apologize for not reading your thread with great care, but I think
that
your problem is pretty clear.
The issue is not to do with gets and puts overlapping. The issue is
that a
put or remove happened during the life of your iterator.
One way to avoid this is to synchronize the entire method that does
the
deletion of old elements. To speed that up, you might just
synchronize
the
scan for elements to delete and collect them into a list. Then you
can
delete them outside the loop. Since your scan is probably pretty
fast,
this
may be sufficient. With very high levels of updates and threading,
it
would
cause problems.
Another option is to clone the table. I believe that some
implementations
of LRUMap in Lucene do copy-on-write semantics, but I don't think
that
collections has these. Without that, cloning will be as slow or
slower
than
Re: Using apache.commons.cli with Java 1.4.2
sebb-2-2 wrote:
On 15/06/2009, esharris eshar...@mac.com wrote:
esharris wrote:
beeky wrote:
I'm jumping in sort of late on this, but here goes.
To locate local config issues do the following.
Create a simple script, call it 'view_cpath.bat', to invoke your app
and
output the classpath before the line that calls your app.
-- begin script (windows batch file example):
echo classpath=%classpath%
java my.org.myapp %*
- end script
invoke your app with view_cpath.bat ... normal arg list ...
With classpath in hand, check the following:
1. is the cli jar file explicitly named in the classpath? *.jar will
not work.
2. is the jar file actually in the place where the classpath says it
should be? Use dir or ls on classpath entries to be sure.
3. check for misspellings of the jar file name in classpath. The
spelling is relative, obviously both classpath entry and actual jar
file
must be spelled the same. Commons jar files have lots of '-' and
'.',
it is easy to get them wrong. I've done it many, many times!
This will find the problem is it is just local configuration.
To make sure you are using the correct jar file do the following.
use 'jar tvf commons-cli-1.1.jar' (from the directory that contain
the
jar file) to view the contents of the jar file. In the output you
should see something like:
423 Wed Jul 04 19:48:06 EDT 2007
org/apache/commons/cli/CommandLineParser.class
If you don't see this you have a bad/wrong jar file. Try downloading
again.
Hope this helps,
-=beeky
esharris wrote:
This the only message:
Exception in thread main java.lang.NoClassDefFoundError:
org/apache/commons/cli/CommandLineParser.
I only have 1.4.2 java on my machine.
Earl
Emmanuel Bourg-3 wrote:
esharris a écrit :
IMHO, NoClassDefFoundError is hard to debug.
Could you paste the full stack trace? Also, check that the code was
compiled with -target 1.4
Emmanuel Bourg
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Initially, there was no CLASSPATH. I added the long name of the
commons-cli-1.2.jar to the class path. The execution of the bat file
displayed the expected class path. But this didn't solve the problem.
I
also introduced a JAVA_HOME environment variable that has the path to
the
jdk.
If I put both jars in the same directory, extract everything out of the
jars, and do a java {path to main class}, it works.
IMHO, my ability to set the class path to a jar is broken. And my
ability to
set the class path to something besides the current directory is broken.
The java command ignores the classpath if you use the -jar option.
This is by design, and is documented:
http://java.sun.com/j2se/1.4.2/docs/tooldocs/windows/java.html#-jar
See the last paragraph for the -jar option.
The problems you are reporting don't seem to be specific to Commons CLI.
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The problem is not specified to a particular jar.
If I want to execute a class file with dependencies, I can do it using class
directories or jar files that are not immediately in the current directory.
I just use the -commandpath option and include the current directory.
If I want to execute a Jar file with dependencies, I can't do it. I need to
learn more about how to get Eclipse to create a manifest containing the
right class pathes.
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Re: [collections] LRUMap Problem ConcurrentModificationException
That's the one, René. Yeah, no real solution in that JIRA issue I'm afraid. :(
But it shows you what's already been looked at.
Otis
--
Sematext -- http://sematext.com/ -- Lucene - Solr - Nutch
- Original Message
From: Renè Glanzer rene.glan...@gmail.com
To: Commons Users List user@commons.apache.org
Sent: Tuesday, June 16, 2009 6:05:26 AM
Subject: Re: [collections] LRUMap Problem ConcurrentModificationException
Hey Otis,
i found this one:
https://issues.apache.org/jira/browse/COLLECTIONS-3
but there is no solutions only an assumption at the end of the thread??
René
2009/6/15 Otis Gospodnetic :
Btw. I think you'll find a report about this from a few years ago in the
Collections JIRA. Just search for my name.
Otis
--
Sematext -- http://sematext.com/ -- Lucene - Solr - Nutch
- Original Message
From: Renè Glanzer
To: Commons Users List
Sent: Monday, June 15, 2009 12:00:54 PM
Subject: Re: [collections] LRUMap Problem ConcurrentModificationException
Yes of course,
the code with the time based cache systems was set up with an ordniary
HashMap. But when rapidly seach requests are
generated the time based mechanism fails to delete old entries - cause
they are not old enough - and so the cache will
raise up until the entire VM memory is used. Then i found the LRUMap
switched to it and bang Exception in my delete method.
When i switch back to HashMap the code runs well - as currently on the
productive system - except the open memory leak.
René
2009/6/15 Leon Rosenberg :
just out of curiosity have you tried the same code with a standard
hashmap?
Leon
On Mon, Jun 15, 2009 at 4:37 PM, Renè Glanzerwrote:
Hello,
side note accepted :-)
In my class I checked the get, put and remove methods. All are
synchronized.
As you can see also the code which wants to delete the elements is
synchronized.
So I've no clue where the ConcurrentModificationException is comming
from
:-(
Thanks René
2009/6/15 Leon Rosenberg :
Hello,
on a side note, generics make reading of code easier :-)
you haven't posted the whole code, but have you (double)checked that
all other acesses to store are synchronized?
regards
Leon
On Mon, Jun 15, 2009 at 2:31 PM, Renè Glanzerwrote:
I'm calling the remove() method on the iterator. I know when i call
the remove on the map itself it will cause the problem with my
currently running iterator, but i'm aware of that.
Here is the code block which should delete old entries:
store: is the LRUMap
birth: is a long which keeps the creation time when this is set to 0
the item should be deleted
public void removeAllExpiredItems()
{
synchronized(this.store)
{
Iterator it=this.store.keySet().iterator();
while(it.hasNext())
{
Object key=it.next();
Object o=this.get(key);
if(o != null)
{
Item iEntry=(Item)this.store.get(key);
if(iEntry.birth==0)
it.remove(); //Here the exception occurs
}
}
this.setLastCleanDate(new Date()); //only to know when the
deleter run the last time
}
}
Thanks for any help :-)
René
2009/6/15 James Carman :
Are you calling remove() on the iterator or on the map itself?
On Mon, Jun 15, 2009 at 6:37 AM, Renè Glanzer
wrote:
Hello,
is there still no help for me?
Is somebody able to explain me, why i get this
java.util.ConcurrentModificationException
on iterating and calling remove() on the LRUMap?
Please
René
2009/6/10 Renè Glanzer :
Hello Ted,
thanks for the fast response. I understand that simultaneously puts
and gets do not cause the exception cause they are synchronized in
my
class.
And my stated code-fragment is the part which wants to delete the
entries from the underlying LRUMap. And my code is wrapped in the
synchronized block. But i think the LRUMap herselfe also iterates
the
entries and this maybe happens at the same time when my iterator is
checking and trying to delete elements. My class is not
implementing
the LRUMap but has one LRUMap as a variable.
So your solution to override the removeLRU(Entry) methode would not
help meunfortunatelly :-(
For now i really do not know how to solve the problem in an easy
way
without refractoring the entire code?
Any other solutions?
Thanks René
2009/6/9 Ted Dunning :
I apologize for not reading your thread with great care, but I
think
that
your problem is pretty clear.
The issue is not to do with gets and puts overlapping. The issue
is
that a
put or remove happened during the life of your iterator.
One way to avoid this is to synchronize the entire method that
does
the
deletion of old elements. To speed
