Newer versions of Java (1.3 and 1.2.2) have different GC algorithms that might
also aid in the clean-up process.
JK
Courtney, James wrote:
Actually, setting a Java object to null (assuming that there are no other
references to that object) is the normal way of telling the VM that the
object may be garbage collected. The garbage collection takes place
asynchronously however and at the discretion of the VM in a background
thread. The act of deleting all references to an object does not free the
memory associated with the object until the garbage collector cleans up the
object.
-Jamey
-Original Message-
From: Jurrius, Mark [mailto:[EMAIL PROTECTED]]
Sent: Thursday, May 03, 2001 7:43 AM
To: [EMAIL PROTECTED]
Subject: RE: Memory usage
Correct me if I'm wrong. If for instance I want a bean removed knowing that
System.gc() does not happen immediately, would setting the bean equal to
null force the bean to be removed from memory right away and not have to
rely on the garbage collection to eventually take place?
Mark
-Original Message-
From: William Kaufman [mailto:[EMAIL PROTECTED]]
Sent: Thursday, May 03, 2001 10:07 AM
To: '[EMAIL PROTECTED]'
Subject:RE: Memory usage
That your finalize method is called, doesn't mean that
the garbage collector has released your objects. The
only way to be shure that this happens, is to explicitly
run System.gc().
Even that's not sufficient: it just suggests to the VM that
garbage-collecting might be a good idea right now. Any actual garbage
collection would take place later, in another thread.
And, even when it does happen, that doesn't mean all the memory will
necessarily be released to the OS: the VM will hold on to some so that it
won't need to go back to the OS on the next allocation.
You might want to get a memory profiler (like JProbe) and see where the
memory is going. At the very least, try doing something like,
Runtime rt = Runtime.getRuntime();
System.err.println(Free=+rt.freeMemory()+,
total=+rt.totalMemory());
often, to see how much memory is actually in use, and how much is just
allocated from the OS.
-- Bill K.
-Original Message-
From: Ralph Einfeldt [mailto:[EMAIL PROTECTED]]
Sent: Thursday, May 03, 2001 5:51 AM
To: '[EMAIL PROTECTED]'
Subject: AW: Memory usage
That your finalize method is called, doesn't mean that
the garbage collector has released your objects. The
only way to be shure that this happens, is to explicitly
run System.gc(). Otherwise it's up to the VM when it will
free the memory. (Sun's JDK per default only releases
memory if otherwise an OutOfMemoryError would occur, so
unless you reach this border the VM will constanly grow)
See also the options for the JVM:
-verbose:gc (Any VM)
-Xincgc (Sun SDK 1.3.*)
-Xms (Sun + IBM)
-Xmx (Sun + IBM)
-Ursprüngliche Nachricht-
Von: Garry De Toffoli [mailto:[EMAIL PROTECTED]]
Gesendet: Donnerstag, 3. Mai 2001 14:34
An: [EMAIL PROTECTED]
Betreff: Memory usage
snip/
I have in trouble with the memory usage with Tomcat 3.21, WinNt 2000
and Jdk 1.3 of Sun. the problem is that any operation does
not release
the memory occuped; to control the memory usage I use the
Task Manager;
when Tomcat start, the memory used from the process Java is of 9608 K;
when I request a Jsp page that has an error, like a variable
not declared,
the memory used is 11868K; if I wait for 1 ay also, this
value does not
change, so the memory used is not released,
running a correct Jsp page, the memory used increase, and this is not
released yet;
I have written a log on the finalize method of my class, and this is
called, so the garbage collector release all my object.
This behavoir is normal?
Probably changing the version of Tomcat this problem may be corrected.
snip/
