$ opera -debugjava
opera: [java] There seems to be a preloaded version of Xt.
       There is a workaround for this problem in the opera
       startup script.  If that workaround fails, opera will
       most likely crash every time it tries to use Java.
       The workaround seems to be working.
       Technical explanation:
       There is a problem with the order of loading Xt and
       Java.  If Xt is loaded before libawt (part of Java),
       Java will crash when it tries to access the screen.
       The workaround is based on using LD_PRELOAD to load
       libawt.so first.

opera: [java] The Java enable flag will not be reset
       because the OPERA_FORCE_JAVA_ENABLED environment
       variable has been defined.

opera: [Java] Adding '/usr/lib/jvm/java-6-sun-1.6.0.00/jre/lib/plugin.jar' to classpath.

(process:4634): GLib-GObject-CRITICAL **: /home/he/Projects/Debian/Packages/pkg-gnome/desktop/experimental/build-area/glib2.0-2.13.5/gobject/gtype.c:2242: initialization assertion failed, use IA__g_type_init() prior to this function

(process:4634): Gtk-CRITICAL **: gtk_clipboard_get_for_display: assertion `GDK_IS_DISPLAY (display)' failed
Adobe FlashPlayer: gtk_clipboard_get(GDK_SELECTION_PRIMARY); failed. Trying to call gtk_init(0,0);
NPN_Invoke toString
NPN_Invoke toString
NPN_Invoke toString
NPN_Invoke toString
#
# An unexpected error has been detected by Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x08179bbf, pid=4479, tid=3070712016
#
# Java VM: Java HotSpot(TM) Client VM (1.6.0-b105 mixed mode)
# Problematic frame:
# C  [opera+0x131bbf]
#
# An error report file with more information is saved as hs_err_pid4479.log
#
# If you would like to submit a bug report, please visit:
#   http://java.sun.com/webapps/bugreport/crash.jsp
#
Aborted