B4J Tutorial MonoBuilder - Compile B4J programs on Linux or Mac

Don't use this builder. It is no longer maintained.

Mono is a Mac / Linux port of .Net Framework: http://www.mono-project.com/

Using Mono it is possible use B4JBuilder, the command line compiler, to compile B4J projects on Linux or Mac.
(The IDE only runs on Windows.)

Installation instructions:

1. Install Mono on the Mac or Linux computer.
2. Install Java JDK. You can check whether it is installed by running javac.
3. Download MonoBuilder: www.b4x.com/b4j/files/MonoBuilder.zip and unzip it.
4. You can now compile the project with the following commands:
export MONO_IOMAP=all
<path to MonoBuilder>/B4JBuilder.exe -task=build

If javac is not found then you should edit b4xV5.ini and set the path to the JDK bin folder.

More information about B4JBuilder: https://www.b4x.com/android/forum/threads/50154/#content

The package includes the libraries that come with the IDE. You can copy other libraries to the libraries folder. The jar files names must be lowercased.

Last edited:


Active Member
Licensed User
Longtime User
Hi to everybody,

I do not know much about Mac and IOS but,
I`m trying to complile B4JBulder in a Mac (Virtual Machine with VirtualBox)

I installed Mono checking for Mac works well.

I have installed Java too.

When I run the command:

export MONO_IOMAP=all
<path to MonoBuilder>/B4JBuilder.exe -task=build

an error occurs as you can see in the attached image

Thanks in advance


  • MonoMac.png
    233.4 KB · Views: 1,008


Licensed User
Longtime User
Are they not two separate commands? Looks like you put them on one line.


Active Member
Licensed User
Longtime User
I am trying to create windows/mac B4J app installers on a Linux VPS for continuous integration. MonoBuilder will be a key part of this. Since the packaged builder is old, I replace with the latest B4JBuilder.exe. But I got System.TypeLoadException.