Java JRE 1.5.0 performance problems with Squid proxy

[broc]

We have a Linux based proxy server running Squid & Dansguardian. This was set up by our LEA support team.

During a recent image refresh of our classroom PCs we upgraded Jave.

Now we are experiencing major performance problems with Java JRE 1.5.0_6 compared to JRE 1.4.2 when students are accessing Samlearning.

Under JRE 1.5.0 The Java 'coffee cup' animation takes forever to load before the Java applet starts, however under 1.4.2 it is very quick.

I have been able to reproduce the problem accessing other websites that use Java which suggests it is not a problem unique to Samlearning.

Looking at the Java console, there are significant delays (7-9secs) following every 'network: Connecting http.....' request.

The problem exists using either IE6 or Firefox browsers. If I tell the browser to bypass the proxy JRE 1.5.0 is almost as fast as JRE 1.4.2.

To me, this points to a problem with the Proxy. Any ideas or suggestions on how to resolve this? Downgrading Java back to 1.4.2 would be a short term bypass, but would be a lot of work & would still leave us with the basic problem.

Brian

[CyberNerd]

I dont have direct experience of this yet, but i looked it up in anticipation that we'll have the same problem with JRE updates.

You should check with the proxy but without the firewall.

http://archlinux.org/pipermail/arch/...er/007409.html
http://forum.java.sun.com/thread.jspa?messageID=3980773

Apparently, the timeout is due to the fact, that the program first tries to use ipv6 instead of ipv4. If your local ipv6 policy is set to block all ipv6 traffic, the java program waits, until the connection is timed out, and the program falls back to ipv4.

[Snuffkins]

We use a linux proxy with squid, but without the firewall and it's fine for us. I've only upgraded a couple of machines so far to test it though, but there's no problems.

[duncane]

Now we are experiencing major performance problems with Java JRE 1.5.0_6 compared to JRE 1.4.2 when students are accessing Samlearning.

Under JRE 1.5.0 The Java 'coffee cup' animation takes forever to load before the Java applet starts...

Could I ask whether you resolved this issue? We're having a similar problem with samlearning.

I'm going to try running an applet from a file URL, and the same applet from my website - hopefully this should narrow down where the problem is likely to be. (Or at least give me enough evidence to say it isn't the JRE itself.)

Sixth day on the job... I'm liking it. People actually thank you for your help - I never got that in my last job

[Wildebeaste]

We've had problems with SamLearning through a proxy - this time using Censornet (squid/dansguardian). I just put it in the list to bypass the authentication and filtering and it's okay now - as much as it will ever be

It helps with all of these 'educational' sites just not to bother filtering. You'll just get a 'vacancy' sign flapping in the breeze if you talk to their support.

[broc]

Now we are experiencing major performance problems with Java JRE 1.5.0_6 compared to JRE 1.4.2 when students are accessing Samlearning.

Under JRE 1.5.0 The Java 'coffee cup' animation takes forever to load before the Java applet starts...

Could I ask whether you resolved this issue? We're having a similar problem with samlearning.

I'm going to try running an applet from a file URL, and the same applet from my website - hopefully this should narrow down where the problem is likely to be. (Or at least give me enough evidence to say it isn't the JRE itself.)

Sixth day on the job... I'm liking it. People actually thank you for your help - I never got that in my last job

We gave up eventually. Our Proxy was built & maintained by our LEA support team. They could reproduce the problem (it affected all Java access, including Samlearning) but they were unable to find a solution. After 9 months of reminding them I gave up & downgraded Java to 1.4.2 (during summer holidays) and the problem went away. We proved that bypassing the proxy for Java fixed the problem but that was not the solution we wanted.

[Ric_]

Have the subsequent releases of Java not helpe you.... JRE 1.5.9 is the latest IIRC.

[Geoff]

Can you give me an example of a site that runs slow? I'll have a tinker here with Java/squid.

[broc]

Try this

www.samlearning.com

then select GCSE from left hand side, then Maths, then Algebra free sample, followed by factorising start

With 1.4.2 we get a grey window opens, with Java coffee cup in top left corner, followed by the student problem displayed maybe 2-4 seconds later.

When we last tried this on 1.5.0 the kids were tearing mouse buttons off with frustration & boredom waiting for the problem to load. it took several minutes.

The problem existed with Firefox and IE6, if I recall correctly bypassing the proxy either in the Java console or at the browser level fixed the performance problem. Looking at the Java console it looked like every request sent to the proxy waits (times out?) and then gets a response. The time delay was very consistent (I think I timed it at something like 6-7 seconds even when there was no load after school).

[broc]

Have the subsequent releases of Java not helpe you.... JRE 1.5.9 is the latest IIRC.

I will try the latest version later today if I get a chance.

[Geoff]

Try this

www.samlearning.com

then select GCSE from left hand side, then Maths, then Algebra free sample, followed by factorising start

With 1.4.2 we get a grey window opens, with Java coffee cup in top left corner, followed by the student problem displayed maybe 2-4 seconds later.

When we last tried this on 1.5.0 the kids were tearing mouse buttons off with frustration & boredom waiting for the problem to load. it took several minutes.

The problem existed with Firefox and IE6, if I recall correctly bypassing the proxy either in the Java console or at the browser level fixed the performance problem. Looking at the Java console it looked like every request sent to the proxy waits (times out?) and then gets a response. The time delay was very consistent (I think I timed it at something like 6-7 seconds even when there was no load after school).

The Java application you mentioned is buggy. It uses the correct Java system calls to pull in some of it's class files but then appears to be hard coded to go direct for the rest. Which of course fails.

Here's the Squid log:

1165312580.181    289 127.0.0.1 TCP_MISS/200 16461 GET http://www.samlearning.com/com/tpl/j...DragDrop.class STMICHAELS\administrator DEFAULT_PARENT/proxy.lancsngfl.ac.uk application/octet-stream
1165312580.403    221 127.0.0.1 TCP_MISS/200 909 GET http://www.samlearning.com/com/tpl/j...ueFilter.class STMICHAELS\administrator DEFAULT_PARENT/proxy.lancsngfl.ac.uk application/octet-stream

Where you can see it's behaving. After these two class files are pulled down it hangs. Then in the console we get:

load: class ShowFile not found.

java.lang.ClassNotFoundException: ShowFile

	at sun.applet.AppletClassLoader.findClass(Unknown Source)

	at sun.plugin.security.PluginClassLoader.findClass(Unknown Source)

	at java.lang.ClassLoader.loadClass(Unknown Source)

	at sun.applet.AppletClassLoader.loadClass(Unknown Source)

	at java.lang.ClassLoader.loadClass(Unknown Source)

	at sun.applet.AppletClassLoader.loadCode(Unknown Source)

	at sun.applet.AppletPanel.createApplet(Unknown Source)

	at sun.plugin.AppletViewer.createApplet(Unknown Source)

	at sun.applet.AppletPanel.runLoader(Unknown Source)

	at sun.applet.AppletPanel.run(Unknown Source)

	at java.lang.Thread.run(Unknown Source)

Caused by: java.io.IOException: open HTTP connection failed.

	at sun.applet.AppletClassLoader.getBytes(Unknown Source)

	at sun.applet.AppletClassLoader.access$100(Unknown Source)

	at sun.applet.AppletClassLoader$1.run(Unknown Source)

	at java.security.AccessController.doPrivileged(Native Method)

	... 11 more

[Geoff]

ok, I've got this working now. I missed the other log entries before.

2006.12.5 9:32:29 administrator 10.81.104.16 http://jdl.sun.com/webapps/getjava/B...t=www.java.com  GET 0 0  1 302 text/html itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk
2006.12.5 9:32:33 administrator 10.81.104.16 http://sunglobal.112.2o7.net/b/ss/su...1802383674092?[AQB]&ndh=1&t=5/11/2006%209%3A32%3A32%202%200&pageName=javac%3ADownload%3AWindowsAuto%3AWin_DownloadLatest&ch=javac%3ADownload&events=event13&products=%3Benglish&h1=javac%3Ajavac%3ADownload&c2=javac%3A&c19=en_javac%3ADownload%3AWindowsAuto%3AWin_DownloadLatest&c20=Download_Help_Pages&c21=NoAds&pid=javac%3AHomepage&pidt=1&oid=http%3A//jdl.sun.com/webapps/getjava/BrowserRedirect%3Flocale%3Den%26host%3Dwww.java.com&ot=A&oi=91&g=http%3A//www.java.com/en/download/windows_ie.jsp&r=http%3A//www.java.com/en/&s=1024x768&c=32&j=1.3&v=Y&k=Y&bw=1024&bh=603&ct=lan&hp=N&[AQE]  GET 0 0  1 302 text/plain itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk
2006.12.5 9:32:36 administrator 10.81.104.16 http://java.sun.com/update/1.5.0/jin...ws-i586-jc.cab *DENIED* Banned extension: .cab GET 0 0 Banned extension. 1 403 text/html itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk
2006.12.5 9:32:36 administrator 10.81.104.16 http://javadl-esd.sun.com/update/1.5...ws-i586-jc.cab *DENIED* Banned extension: .cab GET 0 0 Banned extension. 1 403 text/plain itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk
2006.12.5 9:33:36 administrator 10.81.104.16 http://java.sun.com/update/1.5.0/jin...ws-i586-jc.cab *DENIED* Banned extension: .cab GET 0 0 Banned extension. 1 403 text/html itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk
2006.12.5 9:33:36 administrator 10.81.104.16 http://javadl-esd.sun.com/update/1.5...ws-i586-jc.cab *DENIED* Banned extension: .cab GET 0 0 Banned extension. 1 403 text/plain itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk
2006.12.5 9:33:40 administrator 10.81.104.16 http://java.sun.com/update/1.5.0/1.5.0_09-b03.xml  GET 0 0  1 302 text/html itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk
2006.12.5 9:33:41 administrator 10.81.104.16 http://jdl.sun.com/webapps/download/...re1.5.0_09.msi *DENIED* Banned extension: .msi GET 0 0 Banned extension. 1 403 text/html itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk
2006.12.5 9:33:42 administrator 10.81.104.16 http://jdl.sun.com/webapps/download/...BundleId=10752  GET 0 0  1 302 text/html itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk
2006.12.5 9:33:42 administrator 10.81.104.16 http://sdlc1g.sun.com/servlet/Bridge...GroupName=5PoE  GET 0 0  1 302 text/html itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk
2006.12.5 9:33:43 administrator 10.81.104.16 http://sdlc-esd.sun.com/ESD28/JSCDL/...re1.5.0_09.msi *DENIED* Banned extension: .msi GET 0 0 Banned extension. 1 403 text/plain itsuitepc19.st-michaels-ce23.lancsngfl.ac.uk

It looks like that running the java app requires downloading of extra components from sun. My proxy disallows .cab and .msi file downloads. So I had to whitelist sun.com as an ok download site. As soon as I did that the applet sprung into life.

Does your proxy filter on filetype?

[duncane]

I'm going to try running an applet from a file URL, and the same applet from my website - hopefully this should narrow down where the problem is likely to be. (Or at least give me enough evidence to say it isn't the JRE itself.)

I've tried running a single class applet (to keep it simple) from a file, and from a website. The same applet runs almost instantaneously from the file, and takes about 6-7 seconds via the network and shows the halo'ed coffee-cup. The network isn't that slow

As soon as I did that the applet sprung into life.

When you say 'sprung into life', do you mean it worked, or it worked without any objectionable delay?

Cheers.

[Geoff]

When you say 'sprung into life', do you mean it worked, or it worked without any objectionable delay?

The page loaded instantly as it was cached. I then got a java logo and 'loading' bar. After about 3 sec I was in the java application.

[Inglebob]

With regard to the Samlearning problem;

We've installed jre 1.6 and tested it (all okay)
All IE 7 security looks okay, everthing allowed and the site trusted.
No firewall software or similar running.

When the samlearning site is loaded the console complains of the following:

java.lang.ClassFormatError: Incompatible magic value 218774632 in class file HueFilter
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknow n Source)
at sun.applet.AppletClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.applet.AppletClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at ShowFile.start(ShowFile.java:286)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

This is the same no matter what exercise is loaded.