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From: William R. L. <wr...@ex...> - 2003-09-27 04:12:06
|
Fellow Hibernaters,
I'm receiving an Exception in a Hibernate application I've built, and I'm
a bit confused as to why this might be happening. The code at where the
Exception is thrown is quite simple, and I think this might be a bug in
Hibernate itself. I've searched Google for this to no avail, and I'm
using the latest recommended Hibernate release as available on the site.
The exception I receive has a stacktrace as follows:
java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
at java.util.AbstractList$Itr.remove(Unknown Source)
at net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2101)
at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2061)
at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2005)
at net.sf.hibernate.transaction.JDBCTransaction.commit(
JDBCTransaction.java:57
)
at org.express.ftpsrv.ConnectionHandler.<init>(ConnectionHandler.java:72)
at org.express.ftpsrv.ConnectionListener.accept(ConnectionListener.java:56)
at org.express.ftpsrv.ConnectionListener.main(ConnectionListener.java:19)
And the code at ConnectionHandler.java:72 that causes this looks like:
52:this.ftpSession = new FtpSession();
53:
54:/* ftpSession.setSessionId() does not operate on the unique
55: * 'id' field that is also part of the ftpSession object.
56: */
57:ftpSession.setSessionId(UniqueGenerator.makeUniqueNumber());
58:
59:Date currentDate = new Date();
60:currentDate.setTime(System.currentTimeMillis());
61:this.ftpSession.setBegTime(currentDate);
62:
63:net.sf.hibernate.Session hSession = null;
64:Transaction transaction = null;
65:
66:try
67:{
68: hSession = SessionHolder.getSession();
69:
70: transaction = hSession.beginTransaction();
71: hSession.save(this.session);
72: transaction.commit();
73:} catch (HibernateException e)
74:{
75: transaction.rollback();
76:}
I'd like to point out that this seems to be an intermittent thing,
occurring more often when I instantiate many objects quickly (the quoted
lines 52-72, above, are within a cronstructor in the Object).
Does anyone have any ideas as to what might be happening or where I might
look for additional information in order to track down this bug?
Thanks, in advance, for any response on this.
-- _
__ __ ___ _| | William R. Lorenz <wr...@ex...>
\ V V / '_| | http://www.clevelandlug.net/ ; "Every revolution was
\./\./|_| |_| first a thought in one man's mind." - Ralph Waldo Emerson
|
|
From: Gavin K. <ga...@hi...> - 2003-09-27 10:49:45
|
We seem to be having some problems like this in more than one section
of code. I really don't understand it at all; we suspect some kind of
JVM bug. Unfortunately, no-one has been able to deliver a testcase
that will help me reproduce this on my machine.
I can't really do much, until I can reproduce it.
P.S. You might also get this if you share a session between two
threads - but at least some occurrences of this problem do not seem
to be caused by this....
William R. Lorenz wrote:
>Fellow Hibernaters,
>
>I'm receiving an Exception in a Hibernate application I've built, and I'm
>a bit confused as to why this might be happening. The code at where the
>Exception is thrown is quite simple, and I think this might be a bug in
>Hibernate itself. I've searched Google for this to no avail, and I'm
>using the latest recommended Hibernate release as available on the site.
>
>The exception I receive has a stacktrace as follows:
>
> java.util.ConcurrentModificationException
> at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
> at java.util.AbstractList$Itr.remove(Unknown Source)
> at net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2101)
> at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2061)
> at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2005)
> at net.sf.hibernate.transaction.JDBCTransaction.commit(
> JDBCTransaction.java:57
> )
> at org.express.ftpsrv.ConnectionHandler.<init>(ConnectionHandler.java:72)
> at org.express.ftpsrv.ConnectionListener.accept(ConnectionListener.java:56)
> at org.express.ftpsrv.ConnectionListener.main(ConnectionListener.java:19)
>
>And the code at ConnectionHandler.java:72 that causes this looks like:
>
> 52:this.ftpSession = new FtpSession();
> 53:
> 54:/* ftpSession.setSessionId() does not operate on the unique
> 55: * 'id' field that is also part of the ftpSession object.
> 56: */
> 57:ftpSession.setSessionId(UniqueGenerator.makeUniqueNumber());
> 58:
> 59:Date currentDate = new Date();
> 60:currentDate.setTime(System.currentTimeMillis());
> 61:this.ftpSession.setBegTime(currentDate);
> 62:
> 63:net.sf.hibernate.Session hSession = null;
> 64:Transaction transaction = null;
> 65:
> 66:try
> 67:{
> 68: hSession = SessionHolder.getSession();
> 69:
> 70: transaction = hSession.beginTransaction();
> 71: hSession.save(this.session);
> 72: transaction.commit();
> 73:} catch (HibernateException e)
> 74:{
> 75: transaction.rollback();
> 76:}
>
>I'd like to point out that this seems to be an intermittent thing,
>occurring more often when I instantiate many objects quickly (the quoted
>lines 52-72, above, are within a cronstructor in the Object).
>
>Does anyone have any ideas as to what might be happening or where I might
>look for additional information in order to track down this bug?
>
>Thanks, in advance, for any response on this.
>
>-- _
>__ __ ___ _| | William R. Lorenz <wr...@ex...>
>\ V V / '_| | http://www.clevelandlug.net/ ; "Every revolution was
> \./\./|_| |_| first a thought in one man's mind." - Ralph Waldo Emerson
>
>
>
>-------------------------------------------------------
>This sf.net email is sponsored by:ThinkGeek
>Welcome to geek heaven.
>http://thinkgeek.com/sf
>_______________________________________________
>hibernate-devel mailing list
>hib...@li...
>https://lists.sourceforge.net/lists/listinfo/hibernate-devel
>
>
|
|
From: Juozas B. <ba...@ce...> - 2003-09-28 12:30:16
|
It must be bug in "SessionHolder".
----- Original Message -----
From: "Gavin King" <ga...@hi...>
To: "William R. Lorenz" <wr...@ex...>
Cc: <hib...@li...>;
<hib...@li...>
Sent: Saturday, September 27, 2003 1:48 PM
Subject: Re: [Hibernate] Hibernate Bug? [ConcurrentModificationException]
> We seem to be having some problems like this in more than one section
> of code. I really don't understand it at all; we suspect some kind of
> JVM bug. Unfortunately, no-one has been able to deliver a testcase
> that will help me reproduce this on my machine.
>
> I can't really do much, until I can reproduce it.
>
> P.S. You might also get this if you share a session between two
> threads - but at least some occurrences of this problem do not seem
> to be caused by this....
>
> William R. Lorenz wrote:
>
> >Fellow Hibernaters,
> >
> >I'm receiving an Exception in a Hibernate application I've built, and I'm
> >a bit confused as to why this might be happening. The code at where the
> >Exception is thrown is quite simple, and I think this might be a bug in
> >Hibernate itself. I've searched Google for this to no avail, and I'm
> >using the latest recommended Hibernate release as available on the site.
> >
> >The exception I receive has a stacktrace as follows:
> >
> > java.util.ConcurrentModificationException
> > at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
> > at java.util.AbstractList$Itr.remove(Unknown Source)
> > at net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2101)
> > at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2061)
> > at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2005)
> > at net.sf.hibernate.transaction.JDBCTransaction.commit(
> > JDBCTransaction.java:57
> > )
> > at
org.express.ftpsrv.ConnectionHandler.<init>(ConnectionHandler.java:72)
> > at
org.express.ftpsrv.ConnectionListener.accept(ConnectionListener.java:56)
> > at
org.express.ftpsrv.ConnectionListener.main(ConnectionListener.java:19)
> >
> >And the code at ConnectionHandler.java:72 that causes this looks like:
> >
> > 52:this.ftpSession = new FtpSession();
> > 53:
> > 54:/* ftpSession.setSessionId() does not operate on the unique
> > 55: * 'id' field that is also part of the ftpSession object.
> > 56: */
> > 57:ftpSession.setSessionId(UniqueGenerator.makeUniqueNumber());
> > 58:
> > 59:Date currentDate = new Date();
> > 60:currentDate.setTime(System.currentTimeMillis());
> > 61:this.ftpSession.setBegTime(currentDate);
> > 62:
> > 63:net.sf.hibernate.Session hSession = null;
> > 64:Transaction transaction = null;
> > 65:
> > 66:try
> > 67:{
> > 68: hSession = SessionHolder.getSession();
> > 69:
> > 70: transaction = hSession.beginTransaction();
> > 71: hSession.save(this.session);
> > 72: transaction.commit();
> > 73:} catch (HibernateException e)
> > 74:{
> > 75: transaction.rollback();
> > 76:}
> >
> >I'd like to point out that this seems to be an intermittent thing,
> >occurring more often when I instantiate many objects quickly (the quoted
> >lines 52-72, above, are within a cronstructor in the Object).
> >
> >Does anyone have any ideas as to what might be happening or where I might
> >look for additional information in order to track down this bug?
> >
> >Thanks, in advance, for any response on this.
> >
> >-- _
> >__ __ ___ _| | William R. Lorenz <wr...@ex...>
> >\ V V / '_| | http://www.clevelandlug.net/ ; "Every revolution was
> > \./\./|_| |_| first a thought in one man's mind." - Ralph Waldo Emerson
> >
> >
> >
> >-------------------------------------------------------
> >This sf.net email is sponsored by:ThinkGeek
> >Welcome to geek heaven.
> >http://thinkgeek.com/sf
> >_______________________________________________
> >hibernate-devel mailing list
> >hib...@li...
> >https://lists.sourceforge.net/lists/listinfo/hibernate-devel
> >
> >
>
>
>
> -------------------------------------------------------
> This sf.net email is sponsored by:ThinkGeek
> Welcome to geek heaven.
> http://thinkgeek.com/sf
> _______________________________________________
> hibernate-devel mailing list
> hib...@li...
> https://lists.sourceforge.net/lists/listinfo/hibernate-devel
|
|
From: William R. L. <wr...@ex...> - 2003-09-27 18:29:21
|
On Sat, 27 Sep 2003, Juozas Baliuka wrote:
> It must be bug in "SessionHolder".
Hi, Juozas. That code below was actuallly incorrect in my last email, and
I have corrected it in-line below: I am actually storing this.ftpSession
instead of this.session (line 71 in the original quoted code below).
As for the SessionHolder object, I'm using that so that I don't have
hundreds of connections to the back-end PostgreSQL database. I've include
the code beow -- it should connect to the database if needed and just
return a connected net.sf.hibernate.Session object from its method.
01:public class SessionHolder
02:{
03: private static final boolean DEBUG = true;
04: private static Session session;
05:
06: public static Session getSession()
07: {
08: SessionHolder.connect();
09:
10: return(SessionHolder.session);
11: }
12:
13: public static void connect()
14: {
15: if (SessionHolder.session == null)
16: {
17: try
18: {
19: SessionFactory sessionFactory = new Configuration()
20: .configure().buildSessionFactory();
21: SessionHolder.session = sessionFactory.openSession();
22: } catch (HibernateException e)
23: {
24: if (SessionHolder.DEBUG) e.printStackTrace();
25: }
26: } else
27: {
28: try
29: {
30: SessionHolder.session.reconnect();
31: } catch (Exception e) {}
32: }
33: }
34:
35: public static void disconnect()
36: {
37: if (SessionHolder.session != null)
38: {
39: try
40: {
41: SessionHolder.session.close();
42: SessionHolder.session.disconnect();
43: } catch (HibernateException e) {}
44: }
45: }
46:}
QHat do you think? Is there a better way that I should be doing this
without rewriting a heck of a lot of code? I like the idea of having the
session establishment self-contained within the SessionHolder object?
Does this SessionHolder seem to be the culprit behind the
ConcurrentModificationException issues?
> > We seem to be having some problems like this in more than one section
> > of code. I really don't understand it at all; we suspect some kind of
> > JVM bug. Unfortunately, no-one has been able to deliver a testcase
> > that will help me reproduce this on my machine.
> > I can't really do much, until I can reproduce it.
> > P.S. You might also get this if you share a session between two
> > threads - but at least some occurrences of this problem do not seem to
> > be caused by this....
> > >I'm receiving an Exception in a Hibernate application I've built, and
> > >I'm a bit confused as to why this might be happening. The code at
> > >where the Exception is thrown is quite simple, and I think this might
> > >be a bug in Hibernate itself. I've searched Google for this to no
> > >avail, and I'm using the latest recommended Hibernate release as
> > >available on the site.
> > >The exception I receive has a stacktrace as follows:
> > > java.util.ConcurrentModificationException
> > > at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
> > > at java.util.AbstractList$Itr.remove(Unknown Source)
> > > at net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2101)
> > > at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2061)
> > > at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2005)
> > > at net.sf.hibernate.transaction.JDBCTransaction.commit(
> > > JDBCTransaction.java:57
> > > )
> > > at
> org.express.ftpsrv.ConnectionHandler.<init>(ConnectionHandler.java:72)
> > > at
> org.express.ftpsrv.ConnectionListener.accept(ConnectionListener.java:56)
> > > at
> org.express.ftpsrv.ConnectionListener.main(ConnectionListener.java:19)
> > >
> > >And the code at ConnectionHandler.java:72 that causes this looks like:
> > >
> > > 52:this.ftpSession = new FtpSession();
> > > 53:
> > > 54:/* ftpSession.setSessionId() does not operate on the unique
> > > 55: * 'id' field that is also part of the ftpSession object.
> > > 56: */
> > > 57:ftpSession.setSessionId(UniqueGenerator.makeUniqueNumber());
> > > 58:
> > > 59:Date currentDate = new Date();
> > > 60:currentDate.setTime(System.currentTimeMillis());
> > > 61:this.ftpSession.setBegTime(currentDate);
> > > 62:
> > > 63:net.sf.hibernate.Session hSession = null;
> > > 64:Transaction transaction = null;
> > > 65:
> > > 66:try
> > > 67:{
> > > 68: hSession = SessionHolder.getSession();
> > > 69:
> > > 70: transaction = hSession.beginTransaction();
> > > 71: hSession.save(this.ftpSession);
> > > 72: transaction.commit();
> > > 73:} catch (HibernateException e)
> > > 74:{
> > > 75: transaction.rollback();
> > > 76:}
> > >I'd like to point out that this seems to be an intermittent thing,
> > >occurring more often when I instantiate many objects quickly (the
> > >quoted lines 52-72, above, are within a cronstructor in the Object).
> > >Does anyone have any ideas as to what might be happening or where I
> > >might look for additional information in order to track down this
> > >bug? Thanks, in advance, for any response on this.
-- _
__ __ ___ _| | William R. Lorenz <wr...@ex...>
\ V V / '_| | http://www.clevelandlug.net/ ; "Every revolution was
\./\./|_| |_| first a thought in one man's mind." - Ralph Waldo Emerson
|
|
From: Juozas B. <ba...@ce...> - 2003-09-27 18:46:21
|
Yes, it is problem in SessionHolder implementation, but it is trivial to
fix:
>
> 01:public class SessionHolder
> 02:{
> 03: private static final boolean DEBUG = true;
> 04: private static ThreadLocal session;
> 05:
> 06: public static Session getSession()
> 07: {
> 08: SessionHolder.connect();
> 09:
> 10: return((Session )SessionHolder.session.get());
> 11: }
> 12:
> 13: public static void connect()
> 14: {
> 15: if (SessionHolder.session.get() == null)
> 16: {
> 17: try
> 18: {
> 19: SessionFactory sessionFactory = new Configuration()
> 20: .configure().buildSessionFactory();
> 21: SessionHolder.session.set( sessionFactory.openSession() );
> 22: } catch (HibernateException e)
> 23: {
> 24: throw new RuntimeException(e);
}
> 26: }
}
> 34:
> 35: public static void disconnect()
> 36: {
> 37: if (SessionHolder.session.get() != null)
> 38: {
> 39: try
> 40: {
> 41: SessionHolder.session.close();
> 42: } catch (HibernateException e) {
throw new RuntimeException(e);
}
> 44: }
> 45: }
> 46:}
>
> QHat do you think? Is there a better way that I should be doing this
> without rewriting a heck of a lot of code? I like the idea of having the
> session establishment self-contained within the SessionHolder object?
>
> Does this SessionHolder seem to be the culprit behind the
> ConcurrentModificationException issues?
>
> > > We seem to be having some problems like this in more than one section
> > > of code. I really don't understand it at all; we suspect some kind of
> > > JVM bug. Unfortunately, no-one has been able to deliver a testcase
> > > that will help me reproduce this on my machine.
>
> > > I can't really do much, until I can reproduce it.
>
> > > P.S. You might also get this if you share a session between two
> > > threads - but at least some occurrences of this problem do not seem to
> > > be caused by this....
>
> > > >I'm receiving an Exception in a Hibernate application I've built, and
> > > >I'm a bit confused as to why this might be happening. The code at
> > > >where the Exception is thrown is quite simple, and I think this might
> > > >be a bug in Hibernate itself. I've searched Google for this to no
> > > >avail, and I'm using the latest recommended Hibernate release as
> > > >available on the site.
>
> > > >The exception I receive has a stacktrace as follows:
>
> > > > java.util.ConcurrentModificationException
> > > > at java.util.AbstractList$Itr.checkForComodification(Unknown
Source)
> > > > at java.util.AbstractList$Itr.remove(Unknown Source)
> > > > at
net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2101)
> > > > at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2061)
> > > > at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2005)
> > > > at net.sf.hibernate.transaction.JDBCTransaction.commit(
> > > > JDBCTransaction.java:57
> > > > )
> > > > at
> > org.express.ftpsrv.ConnectionHandler.<init>(ConnectionHandler.java:72)
> > > > at
> > org.express.ftpsrv.ConnectionListener.accept(ConnectionListener.java:56)
> > > > at
> > org.express.ftpsrv.ConnectionListener.main(ConnectionListener.java:19)
> > > >
> > > >And the code at ConnectionHandler.java:72 that causes this looks
like:
> > > >
> > > > 52:this.ftpSession = new FtpSession();
> > > > 53:
> > > > 54:/* ftpSession.setSessionId() does not operate on the unique
> > > > 55: * 'id' field that is also part of the ftpSession object.
> > > > 56: */
> > > > 57:ftpSession.setSessionId(UniqueGenerator.makeUniqueNumber());
> > > > 58:
> > > > 59:Date currentDate = new Date();
> > > > 60:currentDate.setTime(System.currentTimeMillis());
> > > > 61:this.ftpSession.setBegTime(currentDate);
> > > > 62:
> > > > 63:net.sf.hibernate.Session hSession = null;
> > > > 64:Transaction transaction = null;
> > > > 65:
> > > > 66:try
> > > > 67:{
> > > > 68: hSession = SessionHolder.getSession();
> > > > 69:
> > > > 70: transaction = hSession.beginTransaction();
> > > > 71: hSession.save(this.ftpSession);
> > > > 72: transaction.commit();
> > > > 73:} catch (HibernateException e)
> > > > 74:{
> > > > 75: transaction.rollback();
> > > > 76:}
>
> > > >I'd like to point out that this seems to be an intermittent thing,
> > > >occurring more often when I instantiate many objects quickly (the
> > > >quoted lines 52-72, above, are within a cronstructor in the Object).
>
> > > >Does anyone have any ideas as to what might be happening or where I
> > > >might look for additional information in order to track down this
> > > >bug? Thanks, in advance, for any response on this.
>
> -- _
> __ __ ___ _| | William R. Lorenz <wr...@ex...>
> \ V V / '_| | http://www.clevelandlug.net/ ; "Every revolution was
> \./\./|_| |_| first a thought in one man's mind." - Ralph Waldo Emerson
>
>
|
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