Java crashes while accessing X11

[KnisterPeter]

Binary package hint: libxcb-xlib0

I'll use JaserReports to create a PDF report. During this the JVM crashes with the following backtrace:

Locking assertion failure. Backtrace:
#0 /usr/lib/libxcb-xlib.so.0 [0x90740767]
#1 /usr/lib/libxcb-xlib.so.0(xcb_xlib_unlock+0x31) [0x907408b1]
#2 /usr/lib/libX11.so.6(_XReply+0xfd) [0x90a0829d]
#3 /usr/lib/jvm/java-6-sun-1.6.0.04/jre/lib/i386/xawt/libmawt.so [0x8ef548ce]
#4 /usr/lib/jvm/java-6-sun-1.6.0.04/jre/lib/i386/xawt/libmawt.so [0x8ef31067]
#5 /usr/lib/jvm/java-6-sun-1.6.0.04/jre/lib/i386/xawt/libmawt.so [0x8ef31318]
#6 /usr/lib/jvm/java-6-sun-1.6.0.04/jre/lib/i386/xawt/libmawt.so(Java_sun_awt_X11GraphicsEnvironment_initDisplay+0x2f) [0x8ef3161f]
#7 [0xb4c6f3aa]
#8 [0xb4c67f0d]
#9 [0xb4c67f0d]
#10 [0xb4c65249]
#11 /usr/lib/jvm/java-6-sun-1.6.0.04/jre/lib/i386/server/libjvm.so [0x637338d]
#12 /usr/lib/jvm/java-6-sun-1.6.0.04/jre/lib/i386/server/libjvm.so [0x64fd168]
#13 /usr/lib/jvm/java-6-sun-1.6.0.04/jre/lib/i386/server/libjvm.so [0x6373220]
#14 /usr/lib/jvm/java-6-sun-1.6.0.04/jre/lib/i386/server/libjvm.so(JVM_DoPrivileged+0x363) [0x63c90d3]
#15 /usr/lib/jvm/java-6-sun-1.6.0.04/jre/lib/i386/libjava.so(Java_java_security_AccessController_doPrivileged__Ljava_security_PrivilegedAction_2+0x3d) [0xb7c8096d]
#16 [0xb4d0f835]
#17 [0xb4c67da7]
#18 [0xb4c65249]
#19 /usr/lib/jvm/java-6-sun-1.6.0.04/jre/lib/i386/server/libjvm.so [0x637338d]
java: xcb_xlib.c:82: xcb_xlib_unlock: Assertion `c->xlib.lock' failed.

I've using Ubuntu Hardy-Alpha4 und Sun JDK 6.

[KnisterPeter (markus-emedia-solutions-wolf)]

This does not only happen when generating a PDF but also when trying webstart.
It seems like the awt accesses fail.

[KnisterPeter (markus-emedia-solutions-wolf)]

This is a duplicate of bug #87390
https://bugs.launchpad.net/ubuntu/+source/libxcb/+bug/87390