Integrating the Open Java Development Kit

The open source alternative to the Oracle Java SE embedded is the Open Java Development Kit (OpenJDK), an open source implementation of Java SE licensed under the GPLv2, with the classpath exception, which means that applications are allowed to link without being bound by the GPL license.

This recipe will show how to build OpenJDK with Yocto and integrate the JRE into our target images.

Getting ready

The main components of OpenJDK are:

• The HotSpot Java Virtual Machine

• The Java Class Library (JCL)

• The Java compiler, javac

Initially, OpenJDK needed to be built using a proprietary JDK. However, the IcedTea project allowed us to build OpenJDK using the GNU classpath, the GNU compiler for Java (GCJ), and bootstrap a JDK to build OpenJDK. It also complements OpenJDK with some missing components available on Java SE like a web browser plugin and web start implementations.

Yocto can build meta-java using the meta-java layer, which includes recipes for cross-compiling...