Free and Open source tools to build OpenJDK in Windows

OpenJDK is the open source implementation of Java Standard Edition. Oracle (Sun) JDK implementation is going to be based on OpenJDK. OpenJDK and Oracle JDK are almost similar. There are ready made binaries available for Linux distribution but you may need to build OpenJDK on windows.

Below tools are used to build OpenJDK in Windows.

VisualC++ 2010 Express : Compiler used to build the source. This is not open source but you could download it for free. http://www.microsoft.com/visualstudio/en-us/products/2010-editions/visual-cpp-express

Microsoft DirectX SDK : Few DirectX header files are required for compilation.

Java JDK : Bootstrap JDK to build the Java code of OpenJDK. If you want to build OpenJDK 7 you need JDK 6 and If you want to build OpenJDK 8 then you need JDK 7. http://www.oracle.com/technetwork/java/javase/downloads/index.html

Cygwin : It helps to emulate Linux environment. http://cygwin.com

Apache Ant is need as part of the build. http://ant.apache.org/

FreeType develops free, portable and high-quality software solutions for digital typography. http://sourceforge.net/projects/freetype/

Below tools are not mandatory but useful.

NetBeans has some built in support to build OpenJDK. http://www.netbeans.org

TortoiseHG is a Mercurial client used to sync OpenJDK source code. http://tortoisehg.bitbucket.org

Reference:
http://openjdk.java.net/
http://hg.openjdk.java.net/jdk8/jdk8/raw-file/tip/README-builds.html