Building the OpenJDK on Ubuntu 8.10
When I asked a colleague at work what I should do during my vacation, he said build the OpenJDK… so I did!
In hindsight, it would have been easier to have built IcedTea (RedHat’s OpenJDK hybrid) rather than Sun’s raw OpenJDK. However since I spent quite a bit of time setting up the environment I was determined to get it to build.
At a high level I did the following:
- Downloaded the source (~ 85Mb): http://download.java.net/openjdk/jdk7/.
- Downloaded the binary plugins (the bits of the OpenJDK that are yet to be open sourced).
- Downloaded the dependencies.
- Modified some environment variables.
- Checked the environment is ok via the sanity script.
- Made 1 change to the source code.
- Made 1 change to the make compiler flags.
- Ran the build.
The README file did not cover all of the dependencies needed to build the OpenJDK on Ubuntu, here is what worked for me:
- sudo apt-get install build-essential
- sudo apt-get install gawk
- sudo apt-get install m4
- sudo apt-get install libasound2-dev
- sudo apt-get install libcupsys2-dev
- sudo apt-get install sun-java6-jdk
- sudo apt-get install x11proto-print-dev
- sudo apt-get install libxp-dev
- sudo apt-get install libfreetype6-dev
- sudo apt-get install libxt-dev
- sudo apt-get install libxtst-dev
The OpenJDK comes with a script (jdk/make/jdk_generic_profile.sh) to help set up your environment. The main updates I needed to make were:
- The bootjdk variable which holds the folder name of your Java 6 install.
- The jdk_instances variable which holds the parent directory of your bootjdk.
- The binplugs variable which holds the location of the non open source bits of the OpenJDK.
- Ensure ANT_HOME was exported.
- Ensusre ANT_HOME/bin was on the PATH.
You can see my full environment here: jdk_generic_profile.
The environment was then verified using the sanity make target:
$ . jdk/make/jdk_generic_profile.sh $ make sanity
Once this passed I tried building but got a couple of errors.
The first error was:
/openjdk/hotspot/src/share/vm/libadt/port.hpp: In function 'void bcopy(const void*, void*, size_t)': /openjdk/hotspot/src/share/vm/libadt/port.hpp:40: error: 'void bcopy(const void*, void*, size_t)' redeclared inline without 'gnu_inline' attribute /usr/include/bits/string3.h:90: error: 'void bcopy(const void*, void*, size_t)' previously defined here make[6]: *** [incls/_precompiled.incl.gch] Error 1
I understand what the error means but I could not work out why the error occurs because after looking through /usr/include/string.h, the include of /usr/include/bits/string3.h is only done if the user specifies _FORTIFY_SOURCE which as far as I can tell is not done in the OpenJDK. My workaround is quite simple, I commented out the redeclaration of inline void bcopy(const void*, void*, size_t) since it appears to already be inlined somehow.
The second error was:
/openjdk/hotspot/src/share/vm/runtime/arguments.cpp: In static member function 'static void Arguments::set_aggressive_opts_flags()': /openjdk/hotspot/src/share/vm/runtime/arguments.cpp:1359: error: format '%d' expects type 'int', but argument 3 has type 'intx'
This occurs because of a flag that treats WARNINGS as ERRORS. The correct approach would have been to go and fix the warnings, instead I disabled the flag WARNINGS_ARE_ERRORS = -Werror which can be found in hotspot/make/linux/makefiles/gcc.make.
After making these changes I was able to run the build (just typed make) and saw the following output in the end:
Control linux amd64 1.7.0-internal build_product_image build finished: Control linux amd64 1.7.0-internal all_product_build build finished: Control linux amd64 1.7.0-internal all build finished:
I had a working JDK which could be found in build/linux-amd64/j2sdk-image/bin.
$ ./java -version openjdk version "1.7.0-internal" OpenJDK Runtime Environment (build 1.7.0-internal-jeffsinc_2009_01_03_10_52-b00) OpenJDK 64-Bit Server VM (build 14.0-b09, mixed mode)
