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Add a local IntelliJ Project as Dependency for another Project via Maven

I was given a project structure implementing a board game with GUI that contains two Projects/modules in one IntelliJ Project. Both use Maven to manage dependencies.
Module A (Game-Logic)
Module B (Game-gui)
Module A uses Classes in Module B, and A's pom.xml contains the following dependency:
<dependency>
<groupId>io.bibucket.plt</groupId>
<artifactId>Game-gui</artifactId>
<version>0.0.1-SNAPSHOT</version>
<scope>compile</scope>
</dependency>
But Game-gui is just Module B that is contained locally in the Project itself and the infos (groupId,artifactId etc.) are specified in Module B's pom.xml, so that's what it's pointing to!
Why would we specify a maven dependency to it? I thought the point of maven is to manage dependencies to remote artifacts. Is maven also used to specify local dependencies?
During Maven build I see this error:
The POM for io.bibucket.plt:Game-gui:jar:0.0.1-SNAPSHOT is missing, no dependency information available
What does this error mean? Why is this project using Maven to point to a local Module as an artifact?

You need to use install, package and deploy commands of maven for module B to make it accessible for module A. These commands make a .jar file for module B which can be imported by module A. Models and classes in different artifacts can not be visible for each other unless you define their dependencies in pom file of the other module.

Install third party jar in local maven before maven resolves its dependency?

I am working on a multi-module maven project and have third party jar which isn't available in central or public repository, I also even don't want to place on public repo. I am providing following plugin directive in my parent pom to install jar in my local maven repository before its dependency is resolved in child project.
Now I provide dependency in child project as;
But I build the project, it successfully adds dependency in local maven repository (places third party jar in .m2 folder) but the at the same time it gives following error. Looks like, it searches this jar file in child projects libs folder as well, while I have already placed it on root (in myproject.parent/libs).
Failed to execute goal org.apache.maven.plugins:maven-install-plugin:3.0.0-M1:install-file (install-
external-non-maven1-jar) on project myProject.core: The specified file 'C:\Users\myuser\git\MyProjectRepository\myproject.parent\myproject.core\libs\be-ixf-java-sdk-jar-with-dependencies.jar' not exists.
I already know scope and systemPath option but I don't want to use it for some reason.
Kindly help in identifying what I am missing ?

The best approach that you could have if your project have a centralized maven repo like nexus setup is to have your third party library also added to the repo. Now , you are having the bin file added to your project and it's not preferable.
If you already have the required jar under your project code in like : libs\*, then why can't you refer the dependency directly in your pom.xml instead of having to install it in your local maven repo and then use it .
<dependency>
<groupId>anything</groupId>
<artifactId>anything</artifactId>
<version>anything</version>
<scope>system</scope>
<systemPath>${basedir}/lib/jar_name.jar</systemPath>
</dependency>
providing the location of the dependency in your project directory should resolve it during build itself.Look at Maven System dependencies.
Since you do not want to change your current setup . Please bear in mind the following about maven pom structure :
Project Aggregation is similar to Project Inheritance. But instead of
specifying the parent POM from the module, it specifies the modules
from the parent POM. By doing so, the parent project now knows its
modules, and if a Maven command is invoked against the parent project,
that Maven command will then be executed to the parent's modules as
well
So the maven-install-plugin execution that you added in main pom.xml might be getting triggered for all your modules because of this reason. You might want to move that to the module that you actually need this lib to be included in.Read maven doc.
Related : force Maven to copy dependencies into target/lib

How to include the modules in a top-level POM in another project?

I've googled and stack-overflowed everything, but maybe not enough as I'm still not clear how one adds a module of a Maven project as a dependency in another.
So for example let's say we've got:
MajorPager
|___ POM.xml
|___ chuck-commons-core
| |____POM.xml
|____rajni-commons-core
|____POM.xml
Now I want to add chuck-commons-core but not rajni-commons-core. If I do it directly, it can't find the module. So I ran across the following discussions on stack-overflow and my old friend Guggal:
In summary, the below discussions talk of how to create multi-module projects but not really how to include the sub-modules in a top-level POM into another project.
Useful discussions for context
SO Adding a reference to a parent POM project
SO How to add a parent POM as dependency to a different maven project
SO Adding a reference to Parent POM
SO Maven Parent POM vs Modules POM
SO Depend on multi-module aggregator project
SO How to add dependency in Eclipse?
SO How do I configure Maven multi-module-dependency on sub project with different package?
SO How to add a module in parent projects POM as dependency?
SO How to add a dependency in Maven?
Maven dependency mechanism
Maven POM aggregation
Baeldung Multi-module project
Codetab Maven multi-module
Howtodoinjava Maven parent child POM example
Mastertheboss Maven multi-module tutorial
Codetab Multi-module hierarchical project
Sonatype How to share resources across projects
Spring Multi-module project
Concretely, I'd just like a summary from an expert how they add a sub-module of a Parent POM as a dependency to another project.

As of now, I think this is the best solution - to add the following ccodee to the POM.xml of the MajorPager.
Code block 1 incoming
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.teachme.how</groupId>
<artifactId>MajorPager</artifactId>
<version>0.6-SNAPSHOT</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
Code block 2 incoming
<dependencies>
...
<dependency>
<groupId>com.teachme.how</groupId>
<artifactId>norris-commons-core</artifactId>
<version>0.6</version>
</dependency>
...
</dependencies>
When you do so enables Maven to find out where the dependency are - and so Maven picks them up with mvn clean -U install or mvn package -U -DskipTests. And I should like to be educated if this isn't the most effective pattern. Or if any of the fields above are optional that Maven doesn't want me to specify because it can derive it on it's own (say for example, version tag?) - please let me know if that's case as well.

Maven Modules with Variable as Version number

I got a Maven project with the following structure:
Module A (parent), Submodule B and Submodule C
In the parent pom.xml I am using a variable for settings the version of all projects:
...
<version>${revision}</version>
...
<properties>
<revision>1.1</revision>
</properties>
...
<modules>
<module>moduleB</module>
<module>moduleC</module>
</modules>
</project>
Module C is my distribution package which uses the shade plugin for packaging everything into one single jar.
In the submodules I set the parent like this:
<parent>
<groupId>group</groupId>
<artifactId>moduleA</artifactId>
<version>${revision}</version>
</parent>
Now I want to use Module C in another project, however I only get the following error when doing so:
Failed to execute goal on project newProject: Could not resolve dependencies for project group:newProject:jar:0.0.1-SNAPSHOT: Failed to collect dependencies at group:moduleC:jar:1.1: Failed to read artifact descriptor for group:moduleC:jar:1.1: Could not find artifact group:parent:pom:${revision} in nexus (NEXUS_URL)
I assume the problem is, that the variable value is not filled in when referencing Module C as dependency. How can I solve this issue? I already tried to clean the project before building and forcing to update all artifacts without success.

Maven expects all modules to have a hard version.
To avoid editing lots of poms, use the versions plugin, example:
mvn versions:set -DnewVersion=1.0.1
If you run the above command on the parent it will fix all the child poms.
See here for documentation.

Thanks to the comment of hadu.mansouri I could fix it. I used flatten-maven-plugin for flattening the pom.xml files. However, it seems to have a problem with the shade plugin, as the shaded module was the only module where it did not work. Thus, in the released shade module pom it said:
<version>${revision}</version>
for referencing the parent. I used the approach of the article linked in the comment. There, this extension was used: https://github.com/jcgay/unique-revision-maven-filtering
Using this instead of the flatten-maven-plugin, Maven builds the multi module project correctly with the single version property, and I can also use the shaded module in other projects properly.

maven shade plugin custom transformer

Given maven shade plugin resource transformers, how can we create custom ones?
I've tried adding the shade plugin to my pom:
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>2.4.2</version>
</dependency>
And creating a class that implements ResourceTransformer. But when I run it, I get:
[ERROR] Failed to execute goal
org.apache.maven.plugins:maven-shade-plugin:2.4.1:shade (default) on
project foo: Unable to parse configuration of mojo
org.apache.maven.plugins:maven-shade-plugin:2.4.1:shade for parameter
transformers: Cannot load implementation hint
'test.transformer.TestTransformer' -> [Help 1]
The transformer is on the same classpath as the project I'm running the build on, which, I'm guessing is the problem. Is there a way to add in an extension that brings in other transformers?

See in the next section of the instructions:
create a maven project that contains test.transformer.TestTransformer with the appropriate dependencies in its pom.xml.
in the original project project's pom.xml in project.build.plugins.plugin[.id='maven-shade-plugin'] add the above maven project as a dependency.