Introduction to OpenJDK

OpenJDK is an open-source implementation of Oracle's Java Standard Edition platform. OpenJDK is useful for developing Java programs, and provides a complete runtime environment to run Java programs.

This package is known to build and work properly using an LFS-7.7 systemd platform.



A browser plugin and webstart implementation, as well as a pulseaudio sound backend are provided by the Icedtea project. To provide a complete implementation, you will need to later install IcedTea-Web-1.6 and IcedTea-Sound-1.0.1.

OpenJDK is GPL'd code, with a special exception made for non-free projects to use these classes in their proprietary products. In similar fashion to the LGPL, which allows non-free programs to link to libraries provided by free software, the GNU General Public License, version 2, with the Classpath Exception allows third party programs to use classes provided by free software without the requirement that the third party software also be free. As with the LGPL, any modifications made to the free software portions of a third party application, must also be made freely available.



The OpenJDK source includes a very thorough, open source test suite using the JTreg test harness. The testing instructions below allow to test the just built JDK for reasonable compatibility with the proprietary Oracle JDK. However, in order for an independent implementation to claim compatibility, it must pass a proprietary JCK/TCK test suite. No claims of compatibility, even partial compatibility, may be made without passing an approved test suite.

Oracle does provide free community access, on a case by case basis, to a closed toolkit to ensure 100% compatibility with its proprietary JDK. Neither the binary version provided on the Java- page nor the JVM built with the instructions below have been tested against the TCK. Any version that is built using the instructions given, cannot claim to be compatible with the proprietary JDK, without the user applying for, and completing the compatibility tests themselves.

With that in mind, the binaries produced using this build method are regularly tested against the TCK by the members listed on the site above. In addition to the community license above, an educational, non-commercial license for the TCK can be obtained from here.

Source Package Information

The following files may be downladed from the OpenJDK mercurial repository using the addresses<component>/archive/jdk8u51-b16.tar.bz2, where <component> is the name of the JVM component (corba, hostspot, and so on), but that involves renaming the downloaded files, and renaming the extracted directories. For convenience, the BLFS editors have made the files available in an LFS website.

Additional Downloads

OpenJDK Dependencies

Required Dependencies

An existing binary (Java- or an earlier built version of this package), alsa-lib-1.0.29, cpio-2.12, Cups-2.1.0, UnZip-6.0, Which-2.21, Xorg Libraries, and Zip-3.0



Mercurial-3.4.1 and an X Window manager such as twm-1.0.9 (for the tests)

User Notes:

Installation of OpenJDK

Unlike other packages in BLFS, the OpenJDK source packages are distributed in multiple tar balls. You need to first extract the source root from jdk8u51-b16.tar.bz2, change into the extracted directory, then proceed with the following instructions:

tar -xf ../corba.tar.xz      &&
tar -xf ../hotspot.tar.xz    &&
tar -xf ../jaxp.tar.xz       &&
tar -xf ../jaxws.tar.xz      &&
tar -xf ../jdk.tar.xz        &&
tar -xf ../langtools.tar.xz  &&
tar -xf ../nashorn.tar.xz

If you have downloaded the recommended test harness, unpack it too:

tar -xf ../jtreg4.1-b12-356.tar.xz

Fix an issue with the new (since 5.1.0) giflib API:

sed -e 's/DGifCloseFile(gif/&, NULL/' \
    -e '/DGifOpen/s/c)/c, NULL)/'     \
    -i jdk/src/share/native/sun/awt/splashscreen/splashscreen_gif.c

One file in hotspot needs a change, since it relies on a non-normative compiler behavior, which has changed with GCC version 5. Note that the change works also with previous versions.

sed -e 's/(hi - lo)/ hi - lo /' \
    -e 's/(lo - hi)/ lo - hi /' \
    -i hotspot/src/share/vm/opto/type.cpp


Before proceeding, you should ensure that your environment PATH variable contains the location of the Java compilers used for bootstrapping OpenJDK. This is the only requirement for the environment. Modern Java installations do not need JAVA_HOME and CLASSPATH is not used here. Furthermore, OpenJDK developers recommand to unset JAVA_HOME.

The build system does not support the -j switch in MAKEFLAGS.

Configure and build the package with the following commands (--with-milestone value can be modified to fit user preferences):

unset JAVA_HOME               &&
sh ./configure                \
   --with-update-version=51   \
   --with-build-number=b16    \
   --with-milestone=BLFS      \
   --enable-unlimited-crypto  \
   --with-zlib=system         \
   --with-giflib=system       &&
make DEBUG_BINARIES=true                 \
     all  &&
find build/*/images/j2sdk-image -iname \*.diz -delete



Testing will involve the interplay of pairs of JVMs using the networking interface, so networking must be started. If it isn't, not only will these tests fail, but the test cleanup will leave orphaned JVMs running. There will be many of them. Rebooting may be the easiest recovery.

Testing the newly built JVM involves several steps. First, it is better to run the test suite in a frame buffer on a different display, using Xvfb:

if [ -n "$DISPLAY" ]; then
export DISPLAY=:20
nohup Xvfb $DISPLAY                              \
           -fbdir $(pwd)                         \
           -pixdepths 8 16 24 32 > Xvfb.out 2>&1 &
echo $! >
echo Waiting for Xvfb to initialize; sleep 1
nohup twm -display $DISPLAY \
          -f /dev/null > twm.out 2>&1            &
echo $! >
echo Waiting for twm to initialize; sleep 1
xhost +

Then, it is necessary to modify some files:

echo -e "
jdk_all = :jdk_core           \\
          :jdk_svc            \\
          :jdk_beans          \\
          :jdk_imageio        \\
          :jdk_sound          \\
          :jdk_sctp           \\
          com/sun/awt         \\
          javax/accessibility \\
          javax/print         \\
          sun/pisces          \\
          com/sun/java/swing" >> jdk/test/TEST.groups &&
sed -e 's/all:.*jck.*/all: jtreg/'      \
    -e '/^JTREG /s@\$(JT_PLATFORM)/@@'  \
    -i langtools/test/Makefile

Some variables have to be set:

JT_JAVA=$(type -p javac | sed 's@/bin.*@@') &&
JT_HOME=$(pwd)/jtreg                        &&
PRODUCT_HOME=$(echo $(pwd)/build/*/images/j2sdk-image)

The tests are run as follows:

LANG=C make -k -C test                      \
            JT_HOME=${JT_HOME}              \
            JT_JAVA=${JT_JAVA}              \
            PRODUCT_HOME=${PRODUCT_HOME} all
LANG=C ${JT_HOME}/bin/jtreg -a -v:fail,error \
                -dir:$(pwd)/hotspot/test     \
                -k:\!ignore                  \
                -jdk:${PRODUCT_HOME}         \

The test results can be compared to these results, although they usually are run on a newer version. Some failures can be expected, the number of which depends on various conditions, like whether the computer is connected to network. Also, some tests may timeout if the machine is under load.

Next some cleanup has to be done. The instructions below only stop the frame buffer, but it has been reported that some java VM may be left running after the tests, so it is necessary to check orphaned processes:

kill -9 `cat`  &&
kill -9 `cat` &&
rm -f Xvfb.out twm.out &&
rm -f &&
if [ -n "$OLD_DISP" ]; then

Install the package with the following commands as the root user:

cp -RT build/*/images/j2sdk-image /opt/OpenJDK- &&
chown -R root:root /opt/OpenJDK-

There are now two OpenJDK SDKs installed in /opt. You should decide on which one you would like to use as the default. Normally, you would opt for the just installed OpenJDK. If so, do the following as the root user:

ln -sfvn OpenJDK- /opt/jdk

If desired, you may install a .desktop file corresponding to an entry in a desktop menu for policytool. First, you need to obtain an icon from IcedTea-Web-1.6:

tar -xf ../icedtea-web-1.6.tar.gz  \
        icedtea-web-1.6/javaws.png \

Now, as root user:

mkdir -pv /usr/share/applications &&

cat > /usr/share/applications/openjdk-8-policytool.desktop << "EOF" &&
[Desktop Entry]
Name=OpenJDK Java Policy Tool
Name[pt_BR]=OpenJDK Java - Ferramenta de Política
Comment=OpenJDK Java Policy Tool
Comment[pt_BR]=OpenJDK Java - Ferramenta de Política

install -v -Dm644 javaws.png /usr/share/pixmaps/javaws.png

The choice of pt_BR is just an example. You can add any translation by adding lines corresponding to your locale, e.g. for fr_FR, “Name[fr_FR]=” and “Comment[fr_FR]=” with the appropriate text as values.

Command Explanations

sh configure...: the top level configure is a wrapper around the autotools one. It is not executable and must be run through sh.

--with-boot-jdk: This switch provides the location of the temporary JDK. It is normally not needed if java is found in the PATH.

--with-update-version: Currently, the build system does not include the update number in the version string. It has to be specified here.

--with-build-number: Again, the build system does not include the build number in the version string. It has to be specified here too.

--with-milestone: Used to customize the version string.

--enable-unlimited-crypto: Because of limitations on the usage of cryptography in some countries, there is the possibility to limit the size of encryption keys and the use of some algorithms in a policy file. This switch allows to ship a policy file with no restriction. It is the responsability of the user to ensure proper adherence to the law.

--with-zlib=system, --with-giflib=system: Allows to use the system libraries instead of the bundled ones.

--with-jobs=N: Allows setting the number of jobs for make equal to N. The default is the result of a calculation involving the available memory and the number of processors. Note that even if you specify N=1, some parallelization may be used during the build. The SBU given above are with parallel jobs disabled, on a single processor, single core, virtual machine.

--with-cacerts-file=...: Specifies where to find a cacerts file, typically /opt/jdk/jre/lib/security. Otherwise, an empty one is created. You can get it from an earlier version of the package, or use the script below to generate one.

make DEBUG_BINARIES=true DISABLE_HOTSPOT_OS_VERSION_CHECK=ok all: The build fails on 32-bit machines if DEBUG_BINARIES is not set to true. Furthermore, OS version checking in hotspot's Makefile does not account for Linux version 4.x. Disabling the test is harmless and allows building.

find ... -iname '*.diz' -delete: This command removes redundant files.

Configuring OpenJDK

Configuration Information

Normally, the JAVA environment has been configured after installing the binary version, and can be used with the just built package as well. Review Configuring the JAVA environment in case you want to modify something.

To test if the man pages are correctly installed, issue source /etc/profile and man java to display the respective man page.

Install or update the JRE Certificate Authority Certificates (cacerts) file

OpenJDK uses its own format for the CA certificates. Those certificates are located in a file named /opt/jdk/jre/lib/security/cacerts. That file may be generated from the one installed using the instructions on the Certificate Authority Certificates page, using the following procedure. First, generate the mkcacerts script as the root user:

cat > /opt/jdk/bin/mkcacerts << "EOF"
# Simple script to extract x509 certificates and create a JRE cacerts file.

function get_args()
        if test -z "${1}" ; then
            exit 1

        while test -n "${1}" ; do
            case "${1}" in
                -f | --cafile)
                    check_arg $1 $2
                    shift 2
                -d | --cadir)
                    check_arg $1 $2
                    shift 2
                -o | --outfile)
                    check_arg $1 $2
                    shift 2
                -k | --keytool)
                    check_arg $1 $2
                    shift 2
                -s | --openssl)
                    check_arg $1 $2
                    shift 2
                -h | --help)
                    exit 0
                    exit 1

function check_arg()
        echo "${2}" | grep -v "^-" > /dev/null
        if [ -z "$?" -o ! -n "$2" ]; then
            echo "Error:  $1 requires a valid argument."
            exit 1

# The date binary is not reliable on 32bit systems for dates after 2038
function mydate()
        local y=$( echo $1 | cut -d" " -f4 )
        local M=$( echo $1 | cut -d" " -f1 )
        local d=$( echo $1 | cut -d" " -f2 )
        local m

        if [ ${d} -lt 10 ]; then d="0${d}"; fi

        case $M in
            Jan) m="01";;
            Feb) m="02";;
            Mar) m="03";;
            Apr) m="04";;
            May) m="05";;
            Jun) m="06";;
            Jul) m="07";;
            Aug) m="08";;
            Sep) m="09";;
            Oct) m="10";;
            Nov) m="11";;
            Dec) m="12";;


function showhelp()
        echo "`basename ${0}` creates a valid cacerts file for use with IcedTea."
        echo ""
        echo "        -f  --cafile     The path to a file containing PEM"
        echo "                         formated CA certificates. May not be"
        echo "                         used with -d/--cadir."
        echo ""
        echo "        -d  --cadir      The path to a directory of PEM formatted"
        echo "                         CA certificates. May not be used with"
        echo "                         -f/--cafile."
        echo ""
        echo "        -o  --outfile    The path to the output file."
        echo ""
        echo "        -k  --keytool    The path to the java keytool utility."
        echo ""
        echo "        -s  --openssl    The path to the openssl utility."
        echo ""
        echo "        -h  --help       Show this help message and exit."
        echo ""
        echo ""

# Initialize empty variables so that the shell does not pollute the script
today=$( date +%Y%m%d )

# Process command line arguments
get_args ${@}

# Handle common errors
if test "${CAFILE}x" == "x" -a "${CADIR}x" == "x" ; then
    echo "ERROR!  You must provide an x509 certificate store!"
    echo "\'$(basename ${0}) --help\' for more info."
    echo ""
    exit 1

if test "${CAFILE}x" != "x" -a "${CADIR}x" != "x" ; then
    echo "ERROR!  You cannot provide two x509 certificate stores!"
    echo "\'$(basename ${0}) --help\' for more info."
    echo ""
    exit 1

if test "${KEYTOOL}x" == "x" ; then
    echo "ERROR!  You must provide a valid keytool program!"
    echo "\'$(basename ${0}) --help\' for more info."
    echo ""
    exit 1

if test "${OPENSSL}x" == "x" ; then
    echo "ERROR!  You must provide a valid path to openssl!"
    echo "\'$(basename ${0}) --help\' for more info."
    echo ""
    exit 1

if test "${OUTFILE}x" == "x" ; then
    echo "ERROR!  You must provide a valid output file!"
    echo "\'$(basename ${0}) --help\' for more info."
    echo ""
    exit 1

# Get on with the work

# If using a CAFILE, split it into individual files in a temp directory
if test "${CAFILE}x" != "x" ; then
    TEMPDIR=`mktemp -d`

    # Get a list of staring lines for each cert
    CERTLIST=`grep -n "^-----BEGIN" "${CAFILE}" | cut -d ":" -f 1`

    # Get a list of ending lines for each cert
    ENDCERTLIST=`grep -n "^-----END" "${CAFILE}" | cut -d ":" -f 1`

    # Start a loop
    for certbegin in `echo "${CERTLIST}"` ; do
        for certend in `echo "${ENDCERTLIST}"` ; do
            if test "${certend}" -gt "${certbegin}"; then
        sed -n "${certbegin},${certend}p" "${CAFILE}" > "${CADIR}/${certbegin}.pem"
        keyhash=`${OPENSSL} x509 -noout -in "${CADIR}/${certbegin}.pem" -hash`
        echo "Generated PEM file with hash:  ${keyhash}."

# Write the output file
for cert in `find "${CADIR}" -type f -name "*.pem" -o -name "*.crt"`

    # Make sure the certificate date is valid...
    date=$( ${OPENSSL} x509 -enddate -in "${cert}" -noout | sed 's/^notAfter=//' )
    mydate "${date}"
    if test "${certdate}" -lt "${today}" ; then
        echo "${cert} expired on ${certdate}! Skipping..."
        unset date certdate
    unset date certdate
    ls "${cert}"
    certbegin=`grep -n "^-----BEGIN" "${cert}" | cut -d ":" -f 1`
    certend=`grep -n "^-----END" "${cert}" | cut -d ":" -f 1`
    sed -n "${certbegin},${certend}p" "${cert}" > "${tempfile}"
    echo yes | env LC_ALL=C "${KEYTOOL}" -import                     \
                                         -alias `basename "${cert}"` \
                                         -keystore "${OUTFILE}"      \
                                         -storepass 'changeit'       \
                                         -file "${tempfile}"
    rm "${tempfile}"

if test "${TEMPDIR}x" != "x" ; then
    rm -rf "${TEMPDIR}"
exit 0

chmod -v 755 /opt/jdk/bin/mkcacerts


Doing a very large copy/paste directly to a terminal may result in a corrupted file. Copying to an editor may overcome this issue.

Generate the OpenJDK cacerts file as the root user:

if [ -f /opt/jdk/jre/lib/security/cacerts ]; then
  mv /opt/jdk/jre/lib/security/cacerts \
fi &&
/opt/jdk/bin/mkcacerts                 \
        -d "/etc/ssl/certs/"           \
        -k "/opt/jdk/bin/keytool"      \
        -s "/usr/bin/openssl"          \
        -o "/opt/jdk/jre/lib/security/cacerts"

Use the following commands to check if the cacerts file has been successfully installed:

cd /opt/jdk
bin/keytool -list -keystore jre/lib/security/cacerts

At the prompt "Enter keystore password:", press the "Enter" key if there is no keystore password defined. If the cacerts file was installed correctly, you will see a list of the certificates with related information for each one. If not, you need to reinstall them.


Installed Programs: appletviewer, extcheck, idlj, jar, jarsigner, java, javac, javadoc, javah, javap, java-rmi.cgi, jcmd, jconsole, jdb, jdeps, jhat, jinfo, jjs, jmap, jps, jrunscript, jsadebugd, jstack, jstat, jstatd, keytool, mkcacerts, native2ascii, orbd, pack200, policytool, rmic, rmid, rmiregistry, schemagen, serialver, servertool, tnameserv, unpack200, wsgen, wsimport, and xjc
Installed Libraries: /opt/OpenJDK-*, and /opt/OpenJDK-*
Installed Directory: /opt/OpenJDK-

Short Descriptions


allows to run applets outside of a web browser.


checks a specified jar file for title and version conflicts with any extensions installed in the OpenJDK software.


generates Java bindings from a given IDL file.


combines multiple files into a single jar archive.


signs jar files and verifies the signatures and integrity of a signed jar file.


launches a Java application by starting a Java runtime environment, loading a specified class and invoking its main method.


reads class and interface definitions, written in the Java programming language, and compiles them into bytecode class files.


parses the declarations and documentation comments in a set of Java source files and produces a corresponding set of HTML pages describing the classes, interfaces, constructors, methods, and fields.


generates C header and source files that are needed to implement native methods.


disassembles a Java class file.


is the Java RMI client.


is a utility to send diagnostic command requests to a running Java Virtual Machine.


is a graphical console tool to monitor and manage both local and remote Java applications and virtual machines.


is a simple command-line debugger for Java classes.


shows the package-level or class-level dependencies of Java class files.


parses a java heap dump file and allows viewing it in a web browser.


prints Java configuration information for a given Java process, core file, or a remote debug server.


is a command-line tool used to invoke the Nashorn engine. It can be used to interpret one or several script files, or to run an interactive shell.


prints shared object memory maps or heap memory details of a given process, core file, or a remote debug server.


lists the instrumented JVMs on the target system.


is a command line script shell.


attaches to a Java process or core file and acts as a debug server.


prints Java stack traces of Java threads for a given Java process, core file, or a remote debug server.


displays performance statistics for an instrumented JVM.


is an RMI server application that monitors for the creation and termination of instrumented JVMs.


is a key and certificate management utility.


is a simple script to extract x509 certificates and create a JRE cacerts file using keytool.


converts files that contain non-supported character encoding into files containing Latin-1 or Unicode-encoded characters.


is used to enable clients to transparently locate and invoke persistent objects on servers in the CORBA environment.


is a Java application that transforms a jar file into a compressed pack200 file using the Java gzip compressor.


creates and manages a policy file graphically.


generates stub and skeleton class files for remote objects from the names of compiled Java classes that contain remote object implementations.


starts the activation system daemon.


creates and starts a remote object registry on the specified port on the current host.


is a Java XML binding schema generator.


returns the serialVersionUID for one or more classes in a form suitable for copying into an evolving class.


provides an ease-of-use interface for application programmers to register, unregister, startup and shutdown a server.


starts the Java IDL name server.


is a native implementation that transforms a packed file produced by pack200 into a jar file.


generates JAX-WS portable artifacts used in JAX-WS web services.


generates JAX-WS portable artifacts.


is a Java XML binding compiler.

Last updated on 2015-10-13 18:57:40 -0500