Intrepid, Firefox crashes when viewing Java applets. Segmatation fault core dumped.

Same problem, same window in safe mode, but, same cause?

$ firefox -safe-mode
GCJ PLUGIN: thread 0xac5810: NP_Initialize
GCJ PLUGIN: thread 0xac5810: NP_Initialize: using /usr/lib/classpath/gappletviewer.
GCJ PLUGIN: thread 0xac5810: NP_Initialize return
GCJ PLUGIN: thread 0xac5810: GCJ_New
GCJ PLUGIN: thread 0xac5810: plugin_data_new
GCJ PLUGIN: thread 0xac5810: plugin_data_new return
GCJ PLUGIN: thread 0xac5810: plugin_get_documentbase
GCJ PLUGIN: thread 0xac5810: plugin_get_documentbase return
GCJ PLUGIN: thread 0xac5810: plugin_start_appletviewer
GCJ PLUGIN: thread 0xac5810: plugin_start_appletviewer return
exec: 53: /usr/bin/jamvm: not found
Terminado (killed)

jamvm refuses to install 'cause it depends on libffi4 but there is only libffi5 on the repository.

I don't know why but there are 5 different java's installed on my system an niether one works:
          1 /usr/bin/gij-4.3
          2 /usr/lib/jvm/java-gcj/jre/bin/java
 + 3 /usr/lib/jvm/java-6-cacao/jre/bin/java
          4 /usr/bin/gij-4.2
* 5 /usr/lib/jvm/java-6-sun/jre/bin/java

Probably a bug in the gcjwebplugin package rather than in firefox, because...

sudo apt-get remove gcjwebplugin
sudo apt-get autoremove
sudo apt-get install cacao-oj6-plugin

Stops the crash on my system, not sure that it's a good resolution: I'm trying formula1.com's live timing applet and only getting a grey pane at this point.

Does mean Sun's 1.4 demo applets work: http://java.sun.com/applets/jdk/1.4/index.html if you want to test this.

I have to confirm this bug. On intrepid Firefox and Epiphany both crash on java applets when using sun's plugin. The other plugins do work. Firefox does not crash when disabling pretty much all extensions, which is barely acceptable. The other plugins aren't enough for me, however. For example the MDBG Chinese Dictionaries' stroke recognition applet behaves unusable except for sun's JRE. It would be nice to fix this bug in Intrepid.

Obviously bugs like this are opened over and over for more than a week now and there is no "official" recognition of this bug - still "new" still "undecided importance", and not even marked as a duplicate.

Well, hey... but you know, Java Applets aren't that important a technology. And if you really need Java Applets, you can use any one of the other mobile and non-mobile platforms out there except Ubuntu. Obviously it is not even neccessary to mark this bug as "unimportant".

On the ubuntu forums you'll find people unable to access their online banking because of this. Reverting to 32 bit does solve the problem. Hopefully a 64 bit plugin is due this year.

Well there seems to be a lot of confusion about this. I don't think my problem is 64 bit related, because, essentially, I don't have a 64 bit CPU, so it would surprise me a little if Ubuntu installed a 64 bit version of Java on my machine.

When browsing to
  http://www.csse.uwa.edu.au/~john/
I hit a similar problem (attached). This is with 64bit Intrepid, so we crash in 64bit as well. This is a bigger pain in 64bit since GCJ is the only 64bit plugin the Firefox plugin-finder lets you install (it also finds OpenJDK, but refuses to install it).

reopen if this turns out to be firefox's fault ... unlikely that it is though.

Also me, when I try to test my dsl
http://loki06.mpi-sws.mpg.de/bb/bb.php

Ubuntu 8.10 and Firefox 3.0.5

and this is my attachment :)

This also happens when going trying to log into a VPN website of Check Point SSL Network Extender. Which requires the download of an ActiveX / Java control to the browser.

When entering a correct login and password a window pops up asking a question, but cannot read it since firefox crashes before I can get a chance. Below is what I am receiving:

GCJ PLUGIN: thread 0x24d0820: NP_Initialize
GCJ PLUGIN: thread 0x24d0820: NP_Initialize: using /usr/lib/classpath/gappletviewer.
GCJ PLUGIN: thread 0x24d0820: NP_Initialize return
GCJ PLUGIN: thread 0x24d0820: GCJ_New
GCJ PLUGIN: thread 0x24d0820: plugin_data_new
GCJ PLUGIN: thread 0x24d0820: plugin_data_new return
GCJ PLUGIN: thread 0x24d0820: plugin_get_documentbase
GCJ PLUGIN: thread 0x24d0820: plugin_get_documentbase return
gcjwebplugin.cc:978: thread 0x24d0820: Error: Failed to read line from whitelist file.
GCJ PLUGIN: thread 0x24d0820: NP_GetValue
GCJ PLUGIN: thread 0x24d0820: NP_GetValue: returning plugin description.
GCJ PLUGIN: thread 0x24d0820: NP_GetValue return
GCJ PLUGIN: thread 0x24d0820: GCJ_GetValue
GCJ PLUGIN: thread 0x24d0820: GCJ_GetValue: returning TRUE for NeedsXEmbed.
GCJ PLUGIN: thread 0x24d0820: GCJ_GetValue return

(firefox:8900): Gdk-CRITICAL **: gdk_window_get_user_data: assertion `window != NULL' failed

(firefox:8900): Gtk-CRITICAL **: gtk_container_add: assertion `GTK_IS_CONTAINER (container)' failed

(firefox:8900): Gtk-CRITICAL **: gtk_widget_realize: assertion `GTK_WIDGET_ANCHORED (widget) || GTK_IS_INVISIBLE (widget)' failed

(firefox:8900): Gtk-CRITICAL **: gtk_socket_get_id: assertion `GTK_WIDGET_ANCHORED (socket)' failed
Segmentation fault

Confirm this bug, I want play to tribaltrouble2.com (using java applet). When I try - browser closed. In console i see that:

...
Initializing JVM...
NOT IMPLEMENTED: virtual nsresult IcedTeaPluginInstance::Start()
Jar string: /notify_applet.jar
jars length: 1
JNLPRuntime already initialized
Creating NotifyApplet: com.oddlabs.web.notifyclient.NotifyApplet[panel0,0,0,0x0,invalid,layout=java.awt.FlowLayout] 2092843500
Initializing notifier applet com.oddlabs.web.notifyclient.NotifyApplet[panel0,0,0,450x300,invalid,hidden,layout=java.awt.FlowLayout] 2092843500
Listening on address: localhost/127.0.0.1
Connect port: 48183, connect session_id: 6f6570fd5629b35e41b04c011b267f72
Connecting to: tribaltrouble2.com
Logging in as: sid = 'c305f18cf23fc28cee84b8e92a2fb26a'
Segmentation fault

:(

I have the same problem. When I am trying to navigate to mentioned http://www.csse.uwa.edu.au/~john/ or e.g. http://www.plunk.org/~hatch/HyperbolicApplet/ Firefox crashes. It's completely reproducible.

$ firefox
GCJ PLUGIN: thread 0xfc4840: NP_Initialize
GCJ PLUGIN: thread 0xfc4840: NP_Initialize: using /usr/lib/classpath/gappletviewer.
GCJ PLUGIN: thread 0xfc4840: NP_Initialize return
GCJ PLUGIN: thread 0xfc4840: GCJ_New
GCJ PLUGIN: thread 0xfc4840: plugin_data_new
GCJ PLUGIN: thread 0xfc4840: plugin_data_new return
GCJ PLUGIN: thread 0xfc4840: plugin_get_documentbase
GCJ PLUGIN: thread 0xfc4840: plugin_get_documentbase return
gcjwebplugin.cc:978: thread 0xfc4840: Error: Failed to read line from whitelist file.
GCJ PLUGIN: thread 0xfc4840: NP_GetValue
GCJ PLUGIN: thread 0xfc4840: NP_GetValue: returning plugin description.
GCJ PLUGIN: thread 0xfc4840: NP_GetValue return
GCJ PLUGIN: thread 0xfc4840: GCJ_GetValue
GCJ PLUGIN: thread 0xfc4840: GCJ_GetValue: returning TRUE for NeedsXEmbed.
GCJ PLUGIN: thread 0xfc4840: GCJ_GetValue return

(firefox:7843): Gdk-CRITICAL **: gdk_window_get_user_data: assertion `window != NULL' failed

(firefox:7843): Gtk-CRITICAL **: gtk_container_add: assertion `GTK_IS_CONTAINER (container)' failed

(firefox:7843): Gtk-CRITICAL **: gtk_widget_realize: assertion `GTK_WIDGET_ANCHORED (widget) || GTK_IS_INVISIBLE (widget)' failed

(firefox:7843): Gtk-CRITICAL **: gtk_socket_get_id: assertion `GTK_WIDGET_ANCHORED (socket)' failed
Segmentation fault

I have also 64bit Ubuntu 8.10 (Firefox 3.0.8 with gcjwebplugin 0.96.1)
I want to help, but I don't know which informations should I attach or what should I do.

@WillerZ
Yes with the sun 1.4 applets such as blink text I am given a warning dialog. When I click Trust Applet, it takes a while to load but finally works.

On the other hand, when I browse to
  http://www.csse.uwa.edu.au/~john/
firefox crashes the instant the page loads, without even giving the warning dialog.

I have installed some dbgsym packages and I have run two programs:

$ gdb /usr/lib/firefox-3.0.8/firefox 2>&1 | tee gdb.log
$ G_SLICE=always-malloc G_DEBUG=gc-friendly valgrind -v --tool=memcheck --leak-check=full --num-callers=40 --log-file=valgrind.log /usr/lib/firefox-3.0.8/firefox

Logs in attachment.

I'm not a programmer or an expert but just a newbie Ubuntu user.

What I did to get rid of this problem was:
1) Add a Debian repository (deb http://ftp.de.debian.org/debian sid main
non-free) and uncheck any other repository
2) Reload the software list
3) Uninstall every version of java installed and the web plugins (cacao,
icedtea, java, etc)
4) Install sun-java6-bin (6-12-1)
5) remove the Debian repository and check again the standard repositories
6) Voilá, Firefox is runing java applets without crashing

Hopes it helps
Oscar

Intrepid has reached end of life and this plugin has been removed. Are you still having this issue in 12.04 or later?

[Expired for gcjwebplugin (Ubuntu) because there has been no activity for 60 days.]