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import own .jar file as dependency via Maven and have install discover and retrieve it's dependencies

So this is probably a stupid question, but I have created an own library "testlib" which I want to include in other of my own Maven projects.
This is my own librarys .pom
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.test.testlib</groupId>
<artifactId>testlib</artifactId>
<version>1.0-SNAPSHOT</version>
<name>${project.groupId}:${project.artifactId}</name>
<description>testlibrary</description>
<packaging>jar</packaging>
<properties>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.36</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-resources-plugin</artifactId>
<version>2.5</version>
<configuration>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
</build>
</project>
In order to include my library in another new project, I have created a local repository in my new projects .pom
...
<repositories>
<repository>
<id>data-local</id>
<name>data</name>
<url>file://${project.basedir}/repo</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>com.test.testlib</groupId>
<artifactId>testlib</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
</dependencies>
...
Installing my own library "testlib" via mvn install is working fine for testlib itself. The problem is, that Maven will not detect that "testlib" requires org.slf4j, hence won't get it when I run install.
I have checked other dependencies in my .m2 folder and saw they have a .pom file with the same name as the .jar (for log4j that'd be log4j-1.2.17.pom). I tried copying testlibs .pom next to its .jar and changed the name accordinly, but that doesn't do it.
What do I have to do in order to get the same functionality as any other library from maven central? In other words, I don't want a fat .jar that has all dependencies included. I want a Maven project that adds my library as a dependency to discover that it needs sl4j and include it when mvn install is run.

Eclipse (Photon) couldn't find my maven dependency jar

I am trying to import a library from my maven repo. But I got the error saying "The import org cannot be resolved", screenshot below:
However, we can see the jar under the Maven Dependencies from the Package explorer:
Also, my pom.xml looks like:
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>Test1</groupId>
<artifactId>Test1</artifactId>
<version>0.0.1-SNAPSHOT</version>
<build>
<sourceDirectory>src</sourceDirectory>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.7.0</version>
<configuration>
<release>10</release>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.webjars.npm</groupId>
<artifactId>gregorian-calendar</artifactId>
<version>4.1.0</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.8</version>
</dependency>
</dependencies>
</project>
What did I miss here? What else do I need to import org.apache.commons.lang3.time.DateUtils ? Thanks!
Note: I am on Mac

It looks like you have a module-info.java.
In this case, you need to add requires org.apache.commons.lang3; to it (this is the automatic module name from the MANIFEST.MF inside commons-lang3-3.8.jar).
Also, having MainTest1 in the default package is not allowed in a named module, so you have to move it into a package.
Alternatively, you can remove the module-info.java and things should mostly work like before Java 9

Obtaining systemPath from properties file

I'm very new to maven, so kindly bear with me.
i have a maven project with almost 100 dependencies all of which are present in my local system. So I'm adding them to my classpath via pom.xml with <scope> being system and <systemPath> giving path to the said dependencies. A rough structure of my pom.xml looks like this:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com</groupId>
<artifactId>MAVEN_APP</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>MAVEN_APP</name>
<properties>
<jdk.version>1.8</jdk.version>
</properties>
<dependencies>
<dependency>
<groupId>jar1</groupId>
<artifactId>dependency1</artifactId>
<version>0.9.5</version>
<scope>system</scope>
<systemPath>path/to/directory/outside/project/directory/jar1Name.jar</systemPath>
</dependency>
......
<dependency>
<groupId>jar100</groupId>
<artifactId>dependency10</artifactId>
<version>1.9.7</version>
<scope>system</scope>
<systemPath>path/to/directory/outside/project/directory/jar10Name.jar</systemPath>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
This includes all the jars into my classpath and everything is running fine.
But i would like to keep the path/to/directory/outside/project/directory/ inside my app.propeties file and pom.xml should fetch this path from the properties file.
Is there a way in maven to do this.
Could somebody help me here. Thanks in advance.

EAR with WARs containing different versions of dependencies

Here is my requirement
EAR
WAR (Code)
----Dependency A v1
WAR (Code same as WAR above)
----Dependency A v2
AS the code for WAR project is same I don't want to create multiple code base for WAR project. So I'm looking for EAR pom.xml in such a way that maven builds the WAR with dependency A v1 which can be passed as some property while building WAR.
EAR pom.xml
...
(modules)
(webmodule)
(artifact)WAR(/artifact)
dependency version v1
(content-path)/warwithv1(/content-path)
(/webmodule)
(webmodule)
(artifact)WAR(/artifact)
dependency version v2
(content-path)/warwithv2(/content-path)
(/webmodule)
...
Thanks
Sorry for the XML Tags

EDIT: Answer changed after clarification in comments.
The question as I now understand it is: How does one use a single POM to create 2 WAR files that both have the same source code but different dependencies.
The solution I propose is to create a parent POM that will specify one module per WAR. One of the modules will contain the source code for the war and specify one version of dependencies. The second module will refer to the first module for its source code and will specify a second version of dependencies.
Here is my high level project structure:
Here is the top level (parent) POM:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>maven-war-diff-depend</groupId>
<artifactId>maven-war-diff-depend</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>module1</module>
<module>module2</module>
</modules>
</project>
Module1 will specify v2.3 of log4j2, here is its POM:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>maven-war-diff-depend</groupId>
<artifactId>maven-war-diff-depend</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<artifactId>module1</artifactId>
<packaging>war</packaging>
<dependencies>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.3</version>
</dependency>
</dependencies>
</project>
Module2 will specify v2.8.1 of log4j2 and point to module1 for its source code and web.xml file. Note that you may need to do additional work to refer to any other resources in module1 such as adding more maven plugins and configuration.
Here is the module2 POM:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>maven-war-diff-depend</groupId>
<artifactId>maven-war-diff-depend</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<artifactId>module2</artifactId>
<packaging>war</packaging>
<build>
<sourceDirectory>../module1/src/main/java</sourceDirectory>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.2</version>
<configuration>
<webXml>../module1/src/main/webapp/WEB-INF/web.xml</webXml>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.1</version>
</dependency>
</dependencies>
</project>
Note that I only have a single Java class in module1 just to show that in fact this class is compiled and included in both module1 and module2:
Here are the results of a simple clean install build:
Once you have the two WAR files built it's fairly simple to add another module (this would be your EAR) which will include both of the WAR files - I believe that is your final goal.
So, create a third module:
Add the new module to your root level (parent) POM:
<module>module3</module>
Create the necessary configuration in your new module's POM. This involves adding dependencies on the other two artifacts you create with module1 and module2 and configuring the ear plugin as needed.
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>maven-war-diff-depend</groupId>
<artifactId>maven-war-diff-depend</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<artifactId>module3</artifactId>
<packaging>ear</packaging>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-ear-plugin</artifactId>
<version>2.10</version>
<configuration>
<applicationXml>${basedir}/target/application.xml</applicationXml>
<modules>
<webModule>
<groupId>maven-war-diff-depend</groupId>
<artifactId>module1</artifactId>
</webModule>
<webModule>
<groupId>maven-war-diff-depend</groupId>
<artifactId>module2</artifactId>
</webModule>
</modules>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>maven-war-diff-depend</groupId>
<artifactId>module1</artifactId>
<version>0.0.1-SNAPSHOT</version>
<type>war</type>
</dependency>
<dependency>
<groupId>maven-war-diff-depend</groupId>
<artifactId>module2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<type>war</type>
</dependency>
</dependencies>
</project>
Now when you build it will create an EAR that includes the 2 WARs generated by module1 and module2. The ear in this example is simply called module3:
EDIT: Original answer re-added per request in comments.
Here is the POM from the original proposal - using two profiles to specify different dependency versions. As before please note that it's not a good idea to include servlet api inside of a WAR file, it's just being used here as a visual example to show how common dependencies are specified.
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>maven-war-diff-depend</groupId>
<artifactId>maven-war-diff-depend</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<dependencies>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
</dependencies>
<profiles>
<profile>
<id>v2.3</id>
<dependencies>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.3</version>
</dependency>
</dependencies>
</profile>
<profile>
<id>v2.8.1</id>
<dependencies>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.1</version>
</dependency>
</dependencies>
</profile>
</profiles>
</project>

Why is GWT 2.5.1 missing from Maven repo?

I just installed m2e (the Maven Eclipse plugin) and created a new Maven Project with a Quickstart archetype. I then went to the official Maven repo to pull down GWT 2.5.1's dependencies, and see that it wants you to add the following <dependency> element to your project's pom.xml file:
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt</artifactId>
<version>2.5.1</version>
</dependency>
So, altogether, my pom.xml looks like:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.me.myorg</groupId>
<artifactId>maven-resolver</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>maven-resolver</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt</artifactId>
<version>2.5.1</version>
</dependency>
</dependencies>
</project>
I am getting the following error:
Missing artifact com.google.gwt:gwt:jar:2.5.1
And furthermore, in Eclipse's Package Explorer, under my project's Maven Dependencies library, nothing is resolving.
What's going on here? Thanks in advance!
Update: the contents of ~/.m2/repository/com/google/gwt/gwt/2.5.1 are as follows:
gwt-2.5.1.jar.lastUpdated gwt-2.5.1.pom.sha1
gwt-2.5.1.pom _maven.repositories

This gwt dependencie it's a parent pom for the gwt project. This means that the repo will only contain the hash and the pom, but not the jar.
You need to use two libraries: gwt-servlet and gwt-user:
I've found this configuration for GWT development (maybe you don't need to put the <scope> as described):
<dependencies>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-servlet</artifactId>
<version>2.5.1</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-user</artifactId>
<version>2.5.1</version>
<scope>provided</scope>
</dependency>
<dependencies>
Remove your dependencies and update your pom with these two shown above.
You can also use the gwt-maven-plugin to manage your gwt project and deploy via maven. I've found this information there.
I hope that works!