FULL PRODUCT VERSION :
java -version
java version "1.6.0_01"
Java(TM) SE Runtime Environment (build 1.6.0_01-b06)
Java HotSpot(TM) 64-Bit Server VM (build 1.6.0_01-b06, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
uname -a
Linux energy 2.6.21.3cfsv16libatareiser4 #3 SMP Sun Jun 10 16:02:24 CEST 2007 x86_64 AMD Athlon(tm) 64 X2 Dual Core Processor 4600+ AuthenticAMD GNU/Linux


EXTRA RELEVANT SYSTEM CONFIGURATION :
emerge --info
Portage 2.1.2.9 (default-linux/amd64/2007.0, gcc-4.1.2, glibc-2.5-r3, 2.6.21.3cfsv16libatareiser4 x86_64)
=================================================================
System uname: 2.6.21.3cfsv16libatareiser4 x86_64 AMD Athlon(tm) 64 X2 Dual Core Processor 4600+
Gentoo Base System release 1.12.10
Timestamp of tree: Wed, 13 Jun 2007 17:30:01 +0000
ccache version 2.4 [enabled]
dev-java/java-config: 1.3.7, 2.0.33-r1
dev-lang/python: 2.3.6-r2, 2.4.4-r4
dev-python/pycrypto: 2.0.1-r5
dev-util/ccache: 2.4-r7
sys-apps/sandbox: 1.2.18.1
sys-devel/autoconf: 2.13, 2.61
sys-devel/automake: 1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2, 1.10
sys-devel/binutils: 2.17.50.0.16
sys-devel/gcc-config: 1.3.16
sys-devel/libtool: 1.5.23b
virtual/os-headers: 2.6.21
ACCEPT_KEYWORDS="amd64 ~amd64"
AUTOCLEAN="yes"
CBUILD="x86_64-pc-linux-gnu"
CFLAGS="-march=k8 -O2 -msse3 -pipe"
CHOST="x86_64-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/share/X11/xkb /usr/share/config"
CONFIG_PROTECT_MASK="/etc/env.d /etc/env.d/java/ /etc/gconf /etc/revdep-rebuild /etc/terminfo"
CXXFLAGS="-march=k8 -O2 -msse3 -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="autoconfig candy ccache distlocks metadata-transfer parallel-fetch sandbox sfperms strict"
GENTOO_MIRRORS="ftp://ftp.tu-clausthal.de/pub/linux/gentoo/"
LC_ALL="de_DE@euro"
LINGUAS="de"
MAKEOPTS="-j3"
PKGDIR="/usr/portage/packages"
PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --filter=H_**/files/digest-*"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY="/usr/local/portage /usr/local/portage/gentoo-de"
SYNC="rsync://rsync.gentoo.org/gentoo-portage"
USE="3dnow 3dnowext 7zip S3TC X Xaw3d a52 aac acpi addbookmarks aiglx aim aio akode alias alsa altenburgcards amarok amd64 aotuv aqua_theme asf athena audiofile autoreplace bash-completion berkdb binary-drivers bitmap-fonts bluetooth boost bzip2 cairo cdda cddb cdinstall cdparanoia cdr cdrom cdsound cegui cg clamav cli connectionstatus contactnotes cracklib crypt css cups curl dbus depth32 dhcp dio divx dnd double-precision dpms dri dts dv dvd dvdr dvdread emerald emul-linux-x86 encode exif expat exscalibar extra-cardsets fame fasttrack ffmpeg fftw filter_default filter_legacy filter_light flac foomaticdb fortran ftp gadu gdbm gif gimp gimpprint glitz glut glx gnokii gnutella gpgme gpm gtk gtk2 hddtemp highlight history iconv icq id3 imagemagick imlib inotify irc irmc isdnlog jabber java javascript jce jingle joystick jpeg jpeg2k kcal kde kdecards kdeenablefinal kdehiddenvisibility kdepim kdm kexi kipi kqemu lame lcms lesstif libg++ libwww lm_sensors logitech-mouse lzo lzw mad magic maps matroska midi mime mjpeg mmap mmx mmxext mng mp3 mp4 mpeg mpeg2 mplayer msn mudflap mule musepack ncurses neXt net newspr ngui nls no-old-linux nocd nosendmail nowin nowlistening nptl nptlonly nsplugin nvidia offensive ogg openexr opengl openmp oscar pam paste64 pch pcre pdf perl physfs player plugins png pnm posix ppds pppd python qt3 qt4 quicktime rar readline recode reflection reiser4 reiserfs remix resolvconf rogue rtc sametime scanner schedule scsi sdl sdl-sound sdlaudio sendfile server session sharedmem slp smp sms sndfile sockets sounds spell spl sqlite sqlite3 srt sse sse-filters sse2 sse3 ssl startup-notification statistics stats stencil-buffer stroke subp subtitles svg sysfs sysvipc szip tcpd texteffect textures tga theora threads tiff timidity tk toolbar tools transcode translator truetype truetype-fonts type1 type1-fonts unicode unzip usb userlocales utempter v4l v4l2 vcd videos visualization vorbis webdav webpresence wmf wmp wxwindows x264 xanim xcomposite xemacs xext xface xine xml xorg xosd xpm xrandr xscreensaver xskatcards xv xvid xvmc yiff yv12 zlib zvbi" ALSA_CARDS="emu10k1" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mulaw multi null plug rate route share shm softvol" ELIBC="glibc" INPUT_DEVICES="keyboard mouse evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LINGUAS="de" USERLAND="GNU" VIDEO_CARDS="nvidia vesa vga v4l nv"
Unset: CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LANG, LDFLAGS, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS


A DESCRIPTION OF THE PROBLEM :
with AWT_TOOLKIT=MToolkit set jdk 1.6.0_1 causes a segfault on start in several java apps - all that I tried.

riplea
#
# An unexpected error has been detected by Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x000000303c82e5e4, pid=20725, tid=1076017472
#
# Java VM: Java HotSpot(TM) 64-Bit Server VM (1.6.0_01-b06 mixed mode)
# Problematic frame:
# C [libc.so.6+0x2e5e4] catgets+0x14
#
# An error report file with more information is saved as hs_err_pid20725.log
#
# If you would like to submit a bug report, please visit:
# http://java.sun.com/webapps/bugreport/crash.jsp
#
Abgebrochen


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
install the 1.6.0_1 jdk export AWT_TOOLKIT=MToolkit in a shell and try to start any java application with java -jar NAME in that shell results in this segfault.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
none of the apps should segfault. none of the apps segfault with
AWT_TOOLKIT=MToolkit unset.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Attached seperatly

---------- BEGIN SOURCE ----------
get triplea from triplea.sourceforge.net for an example. both their binary as their source version installed with emerge fail with a segfault. Other java apps I tried crash too.

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
do not set AWT_TOOLKIT=MToolkit