Both versions will be installed in parallel. You may choose to keep either or both. Installation of the precompiled JDK is easy: create a directory to install from, copy the .bin there, and run the following commands: 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;