Both versions will be installed in parallel. You may choose to keep either or both. Installation of the precompiled JDK is easy, change the executable bit for the downloaded file, change to the directory where you want it installed and execute the downloaded file. The following (slightly cryptic version) allows automatic installation. VERSION=&j2sdk-bin-version; && MV=`echo $VERSION | cut -d "_" -f 1,1` && V=`echo ${VERSION} | sed -e "s/\./_/g"` && sed -i "s:^PATH=.*::" j2sdk-${V}-linux-i?86.bin && chmod +x j2sdk-${V}-linux-i?86.bin && mkdir -p bin && ln -sf /bin/true bin/more && yes | PATH=$PWD/bin:$PATH ./j2sdk-${V}-linux-i?86.bin && cd j2sdk${VERSION} && install -d /opt/j2sdk/j2sdk-precompiled-${MV} && mv * /opt/j2sdk/j2sdk-precompiled-${MV} The binary version is now installed. If you don't want to compile the source or are not in a postition to download the source owing to license restrictions, skip ahead to the configuration section. Add the recently compiled JDK to the path. export JAVA_HOME=/opt/j2sdk/j2sdk-precompiled-${MV} && export PATH=$PATH:${JAVA_HOME}/bin Unzip the source: VERSION=&j2sdk-src-version; && V=`echo $VERSION | sed -e "s/\./_/g"` && unzip j2sdk-${V}-src-scsl.zip && unzip j2sdk-${V}-mozilla_headers-unix.zip && unzip j2sdk-${V}-bin-scsl.zip Apply all the patches downloaded above. for PATCH in fix-inline-asm-1 gcc33-1 motif-mkmsgcat \ remove-debug-image remove-fixed-paths-1 \ static_cxx do patch -Np1 -i j2sdk-1.4.2-$PATCH.patch done Set/unset some variables which affect the build: export ALT_BOOTDIR="$JAVA_HOME" && unset JAVA_HOME && unset CLASSPATH unset CFLAGS unset CXXFLAGS unset LDFLAGS export ALT_DEVTOOLS_PATH="/usr/bin" && export BUILD_NUMBER="blfs-`date +%s`" && export DEV_ONLY=true && export ALT_MOZILLA_PATH=$PWD && export INSANE=true && export MAKE_VERBOSE=true && export ALT_CACERTS_FILE=${ALT_BOOTDIR}/jre/lib/security/cacerts Setting CFLAGS/CXXFLAGS/LDFLAGS is guaranteed to make the build fail. If you are interested in optimizing the build, set OTHER_CFLAGS/OTHER_CXXFLAGS/OTHER_LDFLAGS instead. Additionally, if you would like to make in parallel, add the following (adjust MAKE_PARALLEL to your liking): export HOTSPOT_BUILD_JOBS=$MAKE_PARALLEL If the included Motif doesn't build properly, the error is noticed much later in the build. A solution is to build the Motif library before compiling the J2SDK. cd motif/lib/Xm && make && cd ../../.. Make and Install J2SDK with the following commands. There will be a lot of messages about missing files that look like errors. As long as the build doesn't stop, the messages are harmless, so ignore them. cd control/make && make && cd ../.. && cd control/build/linux-i?86 && cp -a j2sdk-image /opt/j2sdk/j2sdk-&j2sdk-src-version;