According to this comment in ASTIdentifier, interning was used to lower
memory consumption (heap memory) at the cost of increased memory used in
PermGem. (Are there any numbers to prove it helped reducing memory usage?)
public void setName(String name) {
this.name = name.intern(); // to lower number of strings
this.hash = name.hashCode();
}
Concerning CPU cycles, it's actually faster to avoid calling
String#intern(), see the VisualVM snapshots at [1].
[1] http://jira.openlaszlo.org/jira/browse/LPP-9833
On 4/15/2011 5:06 PM, P T Withington wrote:
This comes from an ancient superstition that string compares were costing us
valuable CPU cycles. If modern Java does that better, feel free to remove the
interns.
On 2011-04-14, at 21:19, Donald Anderson wrote:
Yes, I've noticed this, and thought we should get rid of all those interns.
On Apr 14, 2011, at 8:44 PM, André Bargull wrote:
The compiler also (ab)uses String#intern(), and interned strings are stored in
the PermGen, too. For example every ASTIdentifier's name is interned....
It is definitely the case that Tomcat slowly fills PermGen on each
undeploy/deploy. It's a longstanding problem that has to do with classloaders,
as I recall. The solution is to restart Tomcat.
On 2011-04-14, at 11:40, Raju Bitter wrote:
Thanks, Quirino. It's not the case, but maybe the undeploy/deploy of
the OpenLaszlo webapp is causing the problem. I've increased the
Tomcat PemGen case the JAVA_OPTS and will see if it happens again.
On Thu, Apr 14, 2011 at 5:38 PM, Quirino Zagarese
<quirino.zagarese at gmail.com> wrote:
Such problems may appear when adding new libs to the runtime, since permgen
space should be used to allocate Class objects. Is this the case?
Il giorno 14/apr/2011 17.32, "Raju Bitter"
<r.bitter.mailinglists at googlemail.com> ha scritto:
Using OL trunk, I ran into this error a few times in the past week.
Has anyone else seen that?
org.openlaszlo.sc.CompilerError: tunit/line unknown: , in line: Error:
PermGen space
Which of course is: java.lang.OutOfMemoryError: PermGen space
Restarting Tomcat of course solves the problem, but I don't think I've
seen that in the past.
--
Don Anderson
Java/C/C++, Berkeley DB, systems consultant
voice: 617-306-2057
email: [email protected]
www: http://www.ddanderson.com
blog: http://libdb.wordpress.com
