Create a MicroEJ Firmware From Scratch

in this step: Configure BSP Connection in MicroEJ Application

I followed all the steps in (Configure BSP Connection in MicroEJ Application) and I got the following error:

=============== [ Initialization Stage ] ===============
WARNING: This OS version (Windows 11) has not been tested at the time this package as been built… some functionnalities may not work.
Platform connected to BSP location ‘[absolute_path] to FreeRTOS\FreeRTOS\Demo\CORTEX_LM3S811_GCC’ using application option ‘deploy.bsp.root.dir’.
[INFO ] Launching in Evaluation mode. Your UID is 7833C00321BA47E8.
=============== [ Launching SOAR ] ===============

Could not create type soarTask due to java.lang.ClassFormatError: Class name is empty or contains illegal character in descriptor in class file com/is2t/mowana/soar/product/C

The information is:

What’s the solution?

Hello @hussam,

First I think your deploy.bsp.root.dir property in the file is wrong, it should be set to an absolute path. For example:


I think your error is caused by the version of Java used to build and launch your project. Could you please:

  • Tell me what version of the MicroEJ SDK Dist. you are using.
  • Tell me what MicroEJ architecture you are using.
  • Right-click on your Java project, go to Properties > Java Compiler and make sure that the JDK Compliance is set to Java 1.7.



The distribution I use for MicroEJ SDK is 23.07.
But In the tutorial the prerequisites for the distribution are 20.10

Does it have an effect?

Hello @hussam,

I see that you are launching your application using Java 11 but you use an architecture 7.14.x. Java 11 is supported only with architecture 7.18.x and more and with MicroEJ SDK Dist. 22.06 and more.

You should either upgrade your architecture or use Java 8.

Here is how you can ensure that you are using the right Java version:

  • Go to Window > Preferences > Java > Installed JREs, make sure that a JDK 8 is selected:
  • Before launching your application go to Run > Run Configurations..., select your launcher and go to the JRE tab, make sure that a JDK 8 is selected:


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