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How to compile OpenJDK on Windows

by Sunny Chan


Posted on Sunday July 24, 2011 at 08:42pm in Java


These are the steps that I have made OpenJDK to compile on Windows platform:




  1. Install Visual C++ 2010 Express (or if you are rich, get Visual Studio 2010 Professional) 

  2. Install Windows 7 Platform SDK

  3. Install Cygwin, install the packages suggested on OpenJDK Readme. Also install gcc for step 5

  4. Install DirectX 9.0 SDK

  5. The gnu make package in the current cygwin does not support Windows directory convention and you should compile your own version of the make 3.82 which has the correct support.

  6. Download latest Freetype


    • Compile it using Visual C++ - you can find the Visual C++ project file under <freetype src>/builds/win32/vc2010. 

    • Make sure you have change the type of DLL it generates by going to Project->Properties, then Configuration Manager... button, set it to Release and Win32

    • Make sure you have set it so that it builds a DLL - you can find that under Project->Properties, Configuration Properties, General and there should be a Configuration Type drop down box

    • You can then build freetype. The DLL generated will have a version number attached to it (e.g. freetype245.dll) and you will need to make sure you rename it to freetype.dll.


  7. Get latest Apache ANT

  8. Make sure you have a Java 6 JDK installed

  9. Download the openjdk source code, either using hg or source bundle (I will assume you put it in c:\openjdk)

  10. Open a command prompt for Windows SDK by going to Start -> Windows SDK 7.1 -> Windows SDK 7.1 command prompt

  11. For 32bit ONLY, you should run the Visual Studio compiler settings batch file: c:\program files\Microsoft Visual Studio 10.0\VC\bin\vcvars32.bat

  12. Make sure you have override the standard cygwin bin path so that make.exe you have compiled in step 5 take precedent of the default cygwin.

  13. Also check that the link.exe you run in the path is the actual Microsoft linker and not the cygwin's link command - you will need to fiddle with the path.

  14. Setup a number of environment variables:


    1. ALT_BOOTDIR should point to the Java 6 JDK (Step 8)

    2. ALT_DXSDK_PATH is the DirectX SDK PATH (Step 4)

    3. ALT_FREETYPE_LIB_PATH and ALT_FREETYPE_HEADERS_PATH.

    4. ANT_HOME

    5. HOTSPOT_BUILD_JOBS if you want to parallelize your build - you can't use -j options in the make command

    6. ALLOW_DOWNLOADS=true so that it can download JAXP and JAXS jar

    7. Make sure the path is setup correctly (Step 12/13)


  15. You are ready to give it a go. First, run "make sanity" and see whether there is anything you setup incorrectly. If something is wrong, fix it.

  16. If you have passed make sanity, you can run make to build the JDK! Go and make a cuppa, it will take a while. On my i7-2600 and hard drive it took 2 hours.


Important: In order to build a 32bit JDK you must use a 32bit System - ie. you cannot cross compile (ie. 64bit Windows and compile a 32bit JDK)



Let me know whether it works for you. if it doesn't tell me what's wrong and I will fix the instructions!