Getting Started with MicroEJ

Oderlan Freire — Mon, 27 Sep 2021 16:38:05 +0000

Based on my first contact with MicroEJ technology and a little bit of research, I decided to make a short introduction to this interesting technology. I am going to talk a little bit about the history behind it, where it can be used and how to install and run a Hello World example.

Who is MicroEJ?

MicroEJ is a French company who has created a development application kit focused on embedded systems and IoT, using C, Java® technologies and recently JavaScript® as a programming language. The main objective of this development kit is to help developers create applications for devices which require a high level of performance, compact size, energy efficiency, while still enjoying all the benefits of a high level language such as, Java® or JavaScript®.

Currently, MicroEJ has three products available:

MICROEJ VEE: A virtual machine that can run on devices with very low computing power, including microcontrollers, microprocessors and SoT. It includes free libraries and MEJ32.
MICROEJ SDK: An application development kit, that involves a complete pack of tools and a library, to develop applications that will run on the MICROEJ VEE virtual machine. As well as that, it is possible to create embedded systems simulators called Virtual Devices.
MICROEJ Forge: A cloud technology that helps developers and companies to store applications, assets, libraries and more.

History:

MicroEJ was founded in 2004, by Fred Rivard PhD. and went by the name of Industrial Smart Software Technology (IS2T). After a first phase of research and development, the company grew and raised investment with Innovacom at the end of 2011. The company was renamed to MicroEJ, with the challenge of building a virtualization core that needed to be 1000 times lower than Android, to standardize and viabilize the development of applications to more than 10 billion devices that are fabricated every year, embedded devices and IoT.

Currently, MicroEJ technology runs on 100 million devices, in various industry sectors across manufacturing, smart home, wearables, retail, healthcare, metering, utilities, industrial, consumer, defense, etc.

Installation on Windows(7, 8, 8.1, 10):

To start the installation, first you have to go to the official MicroEJ download page and download the SDK. The site has all the necessary information for installation, including the necessary requirements and information about what comes installed in the SDK. For the SDK to run on your computer, you will need to have JRE8 installed on your PC.

Then just follow the standard Windows installation by clicking next, accept the terms of use, and follow the process by clicking next until you complete the steps and the IDE installation is finished.

Running the basic Hello World in Java:

After starting the IDE, creating a MicroEJ program is quite simple, just go to "File" > "New" > "Standalone Application Project"

Then, give the name of the project and the module name will be filled automatically

When you click "Finish", the Main.java class is built

Since this is a Main class with Hello World, to run it just right-click on the file, "Run As" > "MicroEJ Application".

After running, the console will display the following message:

Hello World!
=============== [ Completed Successfully ] ===============

SUCCESS

Hello World with MicroEJ Template and Emulator

To run the MicroEJ Hello World template, first, you need to install one of the virtual device emulators, in this case, I'll use the NXP OM13098. After downloading it, save it in your workspace. Run the MicroEJ IDE, go to "Window" > "Preferences" > "MicroEJ" > "Virtual Device menu".

The next step is to import the emulator and select the directory where the emulator is saved.

After selection, simply accept the terms of use of the emulator, click "finish", wait for the import process to finish and click "apply and close".The emulator will be installed and ready for use.

To demonstrate the execution of the virtual device, I will use the Hello World template provided by MicroEJ for download. The template comes ready to run, you only need to import the file to the IDE after unzipping it. Unlike the HelloWorld in the first example, this one has to be executed by right-clicking on the folder as it contains more than one file. Follow the same steps: “Run As” > “MicroEJ Application”.

This should be the result in the NXP OM13098 virtual device:

Remember that MicroEJ supports execution on various types of simulators, such as STM32, ESP32 and more.

Conclusion:
MicroEJ is a very interesting technology, focused on development for embedded devices, that makes it possible to run Java® technology on microcontrollers with low computing power and even IoT. It has a very easy installation and setup due to the Java® programming language used. Also the IDE is well known by software developers as they use Eclipse, and they provide a well-organized forum and specific site for developers in addition to its own repository. This provides a great help for those who are starting out or are just curious to know more about how to create Java® applications for MCUs.

I am Oderlan Freire from Ocara, Ceará. I started working at TotalCross in 2021, a student of Information Systems at the Federal University of Ceará, and I participated in the SharinAgro project, one of the top projects selected for the Microsoft contest IA for Earth.

TotalCross: A Powerful Cross-Platform Development Technology

Oderlan Freire — Wed, 18 Aug 2021 21:08:22 +0000

I decided to make this article based on my first few contacts with TotalCross technology. It was something totally new and exciting for me, as I believe it is for all developers, to be able to manipulate a new, robust and powerful technology. In this article I will talk about what TotalCross is, how it works and about TotalCross in VS Code.

What is TotalCross?

TotalCross is a Java based cross-platform SDK technology, aiming to make life easier for the developer or even the common user.It has a very low footprint, taking up a small amount of space on your device, less than 5MB in fact. Being cross-platform, the developer only needs to worry about learning the basics of Java and the TotalCross library to be able to run the program on embedded systems, Windows, Linux, Mac, IOS and Android. It has the same performance with all systems, and doesn't risk changes to the program or how it will behave regardless of the platform.

How it works?

The developer uses the Java language to develop the program code and compile it to generate the Java bytecode. TCVM converts this Java bytecode to TC bytecode, therefore giving a performance boost that is characteristic of TotalCross, thus packaging and distributing it to the desired platform.

TotalCross on VSCode

Starting to developing TotalCross on VSCode is quite simple, just install the TotalCross plugin from VSCode's own marketplace. It is important to know that for the plugin to run well, it is necessary to have JDK11 and Maven installed on your machine.

Creating a project:

After installing JDK11, Maven and the plugin, it's time to start the first project.
Open your VSCode, when the welcome screen appears, press "Ctrl + Shift + P" to open the command palette, type TotalCross and 4 options will appear to you, click Create New Project.

When the file explorer opens, select or create the folder where you want to store the project. You can use a folder in any location, however, I would recommend creating it in the "Documents" directory for better organization.

When you select the folder, the VScode will ask you to enter the GroupId, which is basically the company or user ID. The following format should be used, ".com.company_name/user". For example com.totalcross.

Right after that, it will ask the user to give the program a name:

The next step is to choose the version of the TotalCross SDK, I recommend choosing the most recent one.

Select which platform you want to develop the code for, then press enter or click OK:

Next, VSCode will automatically download a HelloWorld template for you to modify and start developing your program.

How to run the code:

Right-click on the file named RunApplication.java and click on the option Run Java.

VSCode will import, compile and run the Java project, creating the application window:

Conclusion:

I hope you enjoyed this article about TotalCross. After my first contact with this technology, I can say that I recommend it. If you are looking for a new, powerful, accessible and quality technology to develop your program, whether it is cross-platform or not, I strongly recommend TotalCross. This is due to the facilities that the technology offers with its library, easy installation, small footprint, agility, performance increase due to TCVM, and the fact that it has a large community that is on the rise. The TotalCross community is always open to help you learn, exchanging experiences and answering any questions.

You can join the TotalCross community through the official website, GitHub and Discord. It will be a great experience and you are sure to learn a lot of great things! Look forward to seeing you there!

I am Oderlan Freire from Ocara, Ceará. I started working at TotalCross as an intern in 2021, student of Information Systems at the Federal University of Ceará, and I participated in the SharinAgro project, one of the top projects selected for the Microsoft contest IA for Earth.

DEV Community: Oderlan Freire