When I try to emerge rhino (which is a pre-req for ant and therefore most java development tools) I get the error described below. This is using this JDK: blackdown-jdk-1.4.2_rc1 for amd64 I also tried with the unsupported sun-jdk-1.5.0 for amd64 but I got a different error (and is not supported by gentoo). Reproducible: Always Steps to Reproduce: 1.emerge rhino 2. 3. Actual Results: BUILD FAILED java.lang.UnsupportedClassVersionError: org/apache/xerces/jaxp/SAXParserFactoryImpl (Unsupported major.minor version 49.0) at java.lang.ClassLoader.defineClass0(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:537) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123) at java.net.URLClassLoader.defineClass(URLClassLoader.java:251) at java.net.URLClassLoader.access$100(URLClassLoader.java:55) at java.net.URLClassLoader$1.run(URLClassLoader.java:194) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:187) at java.lang.ClassLoader.loadClass(ClassLoader.java:289) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:274) at java.lang.ClassLoader.loadClass(ClassLoader.java:282) at java.lang.ClassLoader.loadClass(ClassLoader.java:235) at javax.xml.parsers.FactoryFinder.newInstance(FactoryFinder.java:93) at javax.xml.parsers.FactoryFinder.find(FactoryFinder.java:174) at javax.xml.parsers.SAXParserFactory.newInstance(SAXParserFactory.java:87) at org.apache.tools.ant.util.JAXPUtils.newParserFactory(JAXPUtils.java:114) at org.apache.tools.ant.util.JAXPUtils.getNSParserFactory(JAXPUtils.java:100) at org.apache.tools.ant.util.JAXPUtils.getNamespaceXMLReader(JAXPUtils.java:163) at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:184) at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:131) at org.apache.tools.ant.ProjectHelper.configureProject(ProjectHelper.java:91) at org.apache.tools.ant.Main.runBuild(Main.java:658) at org.apache.tools.ant.Main.startAnt(Main.java:188) at org.apache.tools.ant.launch.Launcher.run(Launcher.java:196) at org.apache.tools.ant.launch.Launcher.main(Launcher.java:55) Total time: 0 seconds java.lang.UnsupportedClassVersionError: org/apache/xerces/jaxp/SAXParserFactoryImpl (Unsupported major.minor version 49.0) at java.lang.ClassLoader.defineClass0(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:537) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123) at java.net.URLClassLoader.defineClass(URLClassLoader.java:251) at java.net.URLClassLoader.access$100(URLClassLoader.java:55) at java.net.URLClassLoader$1.run(URLClassLoader.java:194) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:187) at java.lang.ClassLoader.loadClass(ClassLoader.java:289) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:274) at java.lang.ClassLoader.loadClass(ClassLoader.java:282) at java.lang.ClassLoader.loadClass(ClassLoader.java:235) at javax.xml.parsers.FactoryFinder.newInstance(FactoryFinder.java:93) at javax.xml.parsers.FactoryFinder.find(FactoryFinder.java:174) at javax.xml.parsers.SAXParserFactory.newInstance(SAXParserFactory.java:87) at org.apache.tools.ant.util.JAXPUtils.newParserFactory(JAXPUtils.java:114) at org.apache.tools.ant.util.JAXPUtils.getNSParserFactory(JAXPUtils.java:100) at org.apache.tools.ant.util.JAXPUtils.getNamespaceXMLReader(JAXPUtils.java:163) at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:184) at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:131) at org.apache.tools.ant.ProjectHelper.configureProject(ProjectHelper.java:91) at org.apache.tools.ant.Main.runBuild(Main.java:658) at org.apache.tools.ant.Main.startAnt(Main.java:188) at org.apache.tools.ant.launch.Launcher.run(Launcher.java:196) at org.apache.tools.ant.launch.Launcher.main(Launcher.java:55) org/apache/xerces/jaxp/SAXParserFactoryImpl (Unsupported major.minor version 49.0) !!! ERROR: dev-java/rhino-1.5.5 failed. !!! Function src_compile, Line 34, Exitcode 1 !!! compilation error detritus rhino # emerge info Portage 2.0.51-r3 (default-linux/amd64/2004.3, gcc-3.4.3, glibc-2.3.4.20040808-r1, 2.6.9-gentoo-r1 x86_64) ================================================================= System uname: 2.6.9-gentoo-r1 x86_64 AMD Athlon(tm) 64 Processor 2800+ Gentoo Base System version 1.4.16 Autoconf: sys-devel/autoconf-2.59-r5 Automake: sys-devel/automake-1.8.5-r1 Binutils: sys-devel/binutils-2.15.90.0.1.1-r3 Headers: sys-kernel/linux26-headers-2.6.8.1-r1 Libtools: sys-devel/libtool-1.5.2-r7 ACCEPT_KEYWORDS="amd64" AUTOCLEAN="yes" CFLAGS="-march=athlon64 -O2 -pipe" CHOST="x86_64-pc-linux-gnu" COMPILER="" CONFIG_PROTECT="/etc /usr/X11R6/lib/X11/xkb /usr/kde/2/share/config /usr/kde/3.3/env /usr/kde/3.3/share/config /usr/kde/3.3/shutdown /usr/kde/3/share/config /usr/lib/mozilla/defaults/pref /usr/share/config /var/qmail/control" CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d" CXXFLAGS="-march=x86-64 -O2 -pipe" DISTDIR="/usr/portage/distfiles" FEATURES="autoaddcvs autoconfig ccache distlocks sandbox" GENTOO_MIRRORS="http://server http://linux.jetstreamgames.co.nz/gentoo http://gentoo.osuosl.org http://www.ibiblio.org/pub/Linux/distributions/gentoo" MAKEOPTS="-j2" PKGDIR="/usr/portage/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="" SYNC="rsync://rsync.gentoo.org/gentoo-portage" USE="amd64 X aalib acpi adns aim alsa apache2 arts artswrappersuid avi bash-completion berkdb bitmap-fonts bonobo bzlib calender cdr crypt cups curl divx4linux dvd dvdr encode esd ethereal f77 fam flac foomaticdb fortran ftp gif gnome gpm gstreamer gtk gtk2 icq imagemagick imap imlib ipv6 jabber jack java joystick jp2 jpeg junit kde kdexdeltas ldap lzw lzw-tiff mad maildir mcal mime mmap mng mozilla mpeg msn multilib ncurses nls nptl offensive oggvorbis openal opengl oscar oss pam pda pdflib perl png python qt quicktime readline samba scanner sdl slang smimespeex spell ssl svg tcpd theora tidy tiff truetype usb userlocales xine xml xml2 xpm xrandr xv xvid yahoo zlib"
Found the problem: I had compiled rhino's dependancies (xerces in particular) with a java 1.5 JDK. Recompiling rhino's dependancies under the blackdown JDK fixed the error. Sorry for wasting your bug space :)
