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-8.0
platform.
![[Note]](../images/note.png)
Note
A browser plugin and webstart implementation is provided by the
Icedtea project. To provide a complete implementation, you will
need to later install IcedTea-Web-1.6.2.
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.
Note
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-1.8.0.121 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
-
OpenJDK Root Package
Download:
http://hg.openjdk.java.net/jdk8u/jdk8u/archive/jdk8u121-b13.tar.bz2
Download MD5 sum: 5f3def798fa3a0b2c60ae891856dc9c5
Download Size: 401 KB
-
In addition to the root package, the instructions below first
download seven subproject tarballs, whose total size is 63
MB.
-
Estimated disk space required: 3.5 GB (additional 420 MB for
tests)
-
Estimated build time: 5 SBU with 4 jobs in parallel (up to
120 SBU for tests, see below)
Additional Downloads
OpenJDK Dependencies
Required Dependencies
An existing binary (Java-1.8.0.121 or an earlier built version of
this package. The instructions below assume that you are using
Configuring the JAVA
environment), alsa-lib-1.1.3, cpio-2.12, Cups-2.2.2, UnZip-6.0, Which-2.21, Xorg Libraries, and
Zip-3.0
Recommended
Certificate Authority
Certificates, giflib-5.1.4, and Wget-1.19.1
Optional
Mercurial-4.1 and an X Window manager such as
twm-1.0.9 (for the tests)
User Notes: http://wiki.linuxfromscratch.org/blfs/wiki/openjdk
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
jdk8u121-b13.tar.bz2, change into the
extracted directory, then proceed with the following instructions:
cat > subprojects.md5 << EOF &&
9c052259b93646687fdcfb71643b69b4 corba.tar.bz2
0ca6e85dcbd96dfa24ac1bdd833aab2e hotspot.tar.bz2
c2b5c1947c4aef684b27a463e4149d06 jaxp.tar.bz2
5a83842eca3881c7bf6abeaccac8f05d jaxws.tar.bz2
4dbe002af94423cbe382dda03e3e6a9d langtools.tar.bz2
0325b88a2b39d7d72ef0726e91ea4a1d jdk.tar.bz2
c87f96bc7ba9596fb5587e307a8f1ec6 nashorn.tar.bz2
EOF
for subproject in corba hotspot jaxp jaxws langtools jdk nashorn; do
wget -c http://hg.openjdk.java.net/jdk8u/jdk8u/${subproject}/archive/jdk8u121-b13.tar.bz2 \
-O ${subproject}.tar.bz2
done &&
md5sum -c subprojects.md5 &&
for subproject in corba hotspot jaxp jaxws langtools jdk nashorn; do
mkdir -pv ${subproject} &&
tar -xf ${subproject}.tar.bz2 --strip-components=1 -C ${subproject}
done
If you have downloaded the optional test harness, unpack it too:
tar -xf ../jtreg-4.2-b05-747.tar.gz
Note
Before proceeding, you should ensure that your environment
PATH variable contains the location of
the Java compilers used for bootstrapping OpenJDK. This is the only requirement for
the environment. Modern Java installations do not need
JAVA_HOME and CLASSPATH is not used here. Furthermore, OpenJDK
developers recommend to unset JAVA_HOME.
The build system does not support the -j switch in MAKEFLAGS.
Configure and build the package with the following commands
(--with-milestone value can be modified to fit user preferences):
unset JAVA_HOME &&
sh ./configure \
--with-update-version=121 \
--with-build-number=b13 \
--with-milestone=BLFS \
--enable-unlimited-crypto \
--with-zlib=system \
--with-giflib=system \
--with-extra-cflags="-std=c++98 -Wno-error -fno-delete-null-pointer-checks -fno-lifetime-dse" \
--with-extra-cxxflags="-std=c++98 -fno-delete-null-pointer-checks -fno-lifetime-dse" &&
make DEBUG_BINARIES=true SCTP_WERROR= all &&
find build/*/images/j2sdk-image -iname \*.diz -delete
Note
Testing will involve the interplay of pairs of JVMs using the
networking interface, so networking must be started. If it isn't,
not only will these tests fail, but the test cleanup will leave
orphaned JVMs running. There will be many of them. Rebooting may
be the easiest recovery.
Testing the newly built JVM involves several steps. First, it is
better to run the test suite in a frame buffer on a different
display, using Xvfb:
if [ -n "$DISPLAY" ]; then
OLD_DISP=$DISPLAY
fi
export DISPLAY=:20
nohup Xvfb $DISPLAY \
-fbdir $(pwd) \
-pixdepths 8 16 24 32 > Xvfb.out 2>&1 &
echo $! > Xvfb.pid
echo Waiting for Xvfb to initialize; sleep 1
nohup twm -display $DISPLAY \
-f /dev/null > twm.out 2>&1 &
echo $! > twm.pid
echo Waiting for twm to initialize; sleep 1
xhost +
Then, it is necessary to modify some files:
echo -e "
jdk_all = :jdk_core \\
:jdk_svc \\
:jdk_beans \\
:jdk_imageio \\
:jdk_sound \\
:jdk_sctp \\
com/sun/awt \\
javax/accessibility \\
javax/print \\
sun/pisces \\
com/sun/java/swing" >> jdk/test/TEST.groups &&
sed -e 's/all:.*jck.*/all: jtreg/' \
-e '/^JTREG /s@\$(JT_PLATFORM)/@@' \
-i langtools/test/Makefile
Some variables have to be set:
JT_JAVA=$(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:${PRODUCT_HOME} \
:jdk
Tests duration depends on various factors such as the network speed
and the number of concurrent VM, which is computed from the number
of cores and threads, and the amount of RAM installed. A maximum of
120 SBU has been observed, but it may be as “low” as 80 SBU.
The test results can be compared to these
results, although they usually are run on a newer version. Some
failures can be expected, the number of which depends on various
conditions, like whether the computer is connected to network.
Also, some tests may timeout if the machine is under load. Those
are the reasons for considering the tests optional, although we
would rather recommend them.
Next some cleanup has to be done. The instructions below only stop
the frame buffer, but it has been reported that some java VM may be
left running after the tests, so it is necessary to check orphaned
processes:
kill -9 `cat twm.pid` &&
kill -9 `cat Xvfb.pid` &&
rm -f Xvfb.out twm.out &&
rm -f Xvfb.pid twm.pid &&
if [ -n "$OLD_DISP" ]; then
DISPLAY=$OLD_DISP
fi
Install the package with the following commands as the root user:
cp -RT build/*/images/j2sdk-image /opt/OpenJDK-1.8.0.121 &&
chown -R root:root /opt/OpenJDK-1.8.0.121
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 -v -nsf OpenJDK-1.8.0.121 /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-1.6.2:
tar -xf ../icedtea-web-1.6.2.tar.gz \
icedtea-web-1.6.2/javaws.png \
--strip-components=1
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
Exec=/opt/jdk/bin/policytool
Terminal=false
Type=Application
Icon=javaws
Categories=Settings;
EOF
install -v -Dm0644 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
responsibility 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-extra-cflags=...
--with-extra-cxxflags=...: Works around some defects in
the code brought to light by the GCC 6 more rigorous checking of
the C/C++ constructs. Remove those switches if compiling with GCC
5.
--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 N=4, on a single processor, 4-core, virtual machine, with
4 GB of memory.
--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 SCTP_WERROR=
all: The build fails on 32 bit machines if
DEBUG_BINARIES is not set to true. Unsetting SCTP_WERROR is part of
the workarounds needed to use GCC 6. You may omit that part of the
command if using GCC 5.
find ... -iname '*.diz'
-delete: This command removes redundant files.