checking if /opt/sun-jdk-1.6.0.03/bin/javac works... configure: error: The Java compiler /opt/sun-jdk-1.6.0.03/bin/javac failed (see config.log, check the CLASSPATH?)

!!! Please attach the following file when filing a report to bugs.gentoo.org:
!!! /home/duro/portage/portage/sys-libs/db-4.5.20_p2/work/db-4.5.20/build_unix/config.log
 * 
 * ERROR: sys-libs/db-4.5.20_p2 failed.
 * Call stack:
 *             ebuild.sh, line 1701:  Called dyn_compile
 *             ebuild.sh, line 1039:  Called qa_call 'src_compile'
 *             ebuild.sh, line   44:  Called src_compile
 *   db-4.5.20_p2.ebuild, line   98:  Called econf '--prefix=/usr' '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--datadir=/usr/share' '--sysconfdir=/etc' '--localstatedir=/var/lib' '--libdir=/usr/lib' '--enable-compat185' '--without-uniquename' '--enable-rpc' '--host=i686-pc-linux-gnu' '--enable-cxx' '--enable-tcl' '--with-tcl=/usr/lib' '--enable-java' '--with-java-prefix=/opt/sun-jdk-1.6.0.03' '--build=i686-pc-linux-gnu' '--disable-test' '-with-javac-flags=-source 1.4 -target 1.4'
 *             ebuild.sh, line  638:  Called die
 * The specific snippet of code:
 *                      die "econf failed"
 *  The die message:
 *   econf failed
 * 
 * If you need support, post the topmost build error, and the call stack if relevant.
 * A complete build log is located at '/home/duro/portage/portage/sys-libs/db-4.5.20_p2/temp/build.log'.
 * 
!!! When you file a bug report, please include the following information:
GENTOO_VM=sun-jdk-1.6  CLASSPATH="." JAVA_HOME="/opt/sun-jdk-1.6.0.03"
JAVACFLAGS="-source 1.4 -target 1.4" COMPILER=""
and of course, the output of emerge --info