How to install JAVA JDK

The goal of this page is to describe the way to install the openJDK on your STM32 MPU board and your desktop (native), in a Distribution Package Environment. It is the "open Standard Edition Java Development Kit" installation process. According to the openstlinux-weston software architecture, we use xwayland for all Java application based on X11, means AWT/SWING Java display/graphical applications. By default the Java Development Kit is installed on the rootfs partition of the target.

1. Prerequisites

• one MPU board
• the STM32MP1 Distribution Package
• an Internet connection
• a Computer with Linux OS Ubuntu

2. Add the yoctoproject meta-java in your environment

JAVA for Linux-based system for embedded system is available as a meta data in yoctoproject. The tar file can be loaded from the Internet site yoctoproject
Download the file release linked to your yocto baseline (example meta-java-rocko.tar.gz for the yocto branch rocko). You are able to select the last commit on the right branch, in the "summary" menu option on the "index:meta-java" page.

• Untar the file in your distribution software environment :

In the following example we install the "meta-java" component for yocto rocko released in the "meta-st" folder. The <TOP-DIR> is the folder you installed your Distribution Package.

 cd <TOP-DIR>/meta-st
 tar -xf  meta-java-rocko.tar.gz

• If not done, setup your build environment

 cd <TOP-DIR>
 source ./meta-st/script/envsetup.sh 
(Select for the DISTRO openstlinux-weston and for MACHINE stm32mp1)

• Add the meta layer in your yocto environment

 cd <TOP-DIR>/build-openstlinuxweston-stm32mp1
 bitbake-layers add-layer <top-DIR>/meta-st/meta-java-rocko

• Define at least the following variables in a distro include file or local.conf

(<TOP-DIR>/build-openstlinuxweston-stm32mp1/conf/local.conf)

#Possible provider: cacao-initial-native and jamvm-initial-native
PREFERRED_PROVIDER_virtual/java-initial-native = "cacao-initial-native"

#Possible provider: cacao-native and jamvm-native
PREFERRED_PROVIDER_virtual/java-native = "jamvm-native"

#Optional since there is only one provider for now
PREFERRED_PROVIDER_virtual/javac-native = "ecj-bootstrap-native"

• Include in your image the openjdk-8 component

 cd <TOP-DIR>/meta-st/meta-st-openstlinux/recipes-st/images

Edit the file st-image-weston.bb and add the following line under CORE_IMAGE_EXTRA_INSTALL
openjdk-8 \

• Build the image

 cd <TOP-DIR>/build-openstlinuxweston-stm32mp1
 bitbake st-image-weston

3. Compil and execute some demo

The target has to be connected on ethernet, the target IP address <YOUR_TARGET_IP> is read with the following command to execute in a linux weston console.

 ifconfig 

• Go to deb package folder :

 cd <TOP-DIR>/build-openstlinuxweston-stm32mp1/tmp-glibc/deploy/deb/cortexa7hf-neon-vfpv4

• Copy the openjdk-8-demo package on the target :

 scp openjdk-8-demo_102b14-r0_armhf.deb  root@<YOUR_TARGET_IP>:/home/root/

• Install the openjdk-8-demo package  :

On a target linux console, executes the command :

 dpkg -i openjdk-8-demo_102b14-r0_armhf.deb

• forkjoin benchmark Java application

 cd /usr/lib/jvm/openjdk-8/sample/forkjoin/mergesort
 javac MergeDemo.java
 java MergeDemo 200 100 3 1 1 3
Running with parameters: 200 100 3 1 1 3
Time in milliseconds. Y-axis: number of elements. X-axis parallelism used.
            1    2    3
    200:   10    7    8
    300:   17   12   12
    400:   20   14   14
  Total:   47   33   34

• SampleTree Java application

Read the README.txt file for details

 cd /usr/lib/jvm/openjdk-8/demo/jfc/SampleTree
 java -jar SampleTree.jar

Microprocessor Unit

Operating System