Dependencies in fat jar not working outside of IDE (Java 8) - javafx

Question

So im working on this JavaFx application (Java 8) which copies a .xlsx file and fills it with data from a .txt-file, for this I use the apache poi dependency. I have successfully build a fat jar through the maven-assembly-plugin. Here my pom.xml:
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>8</source>
<target>8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.1.1</version>
<configuration>
<archive>
<manifest>
<mainClass>sample.Main</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.17</version>
</dependency>
</dependencies>
I build it with:
mvn clean compile assembly:single
The application and its dependencies work fine when I run the main.java in IntelliJ, also the built fat jar starts and works fine when I run it through IntelliJ (performes all functions without a problem).
Only when I start my fat jar outside of the IDE, through a cmd-file (to start the JavaFx application), I'm encountering problems. It starts and loads the .txt-file just fine, but at the point where it's supposed to use the dependency and create a worksheet the program does nothing. Here's what I run in .cmd-file:
start javaw -jar ExcelConverter-1.0-jar-with-dependencies.jar
I've tried building it with various other plugins (shade etc), all seem to have the same problem.
I've also tried building it through intelliJ as an artifact, same issue.
Dependency order is also not an issue as I only use one.

Answer 1

use maven shade plugin for this .check http://maven.apache.org/plugins/maven-shade-plugin/index.html.
below is the sample
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.2.4</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
</plugin>

Answer 2

The problem wasn't the plugins or dependencies not working but that the apache-poi dependency was too memory intensive and thus my JVM ran out of memory. The IntelliJ IDE I've installed uses JVM 64-bit by default, my system on the other hand was using a 32-bit version. I was able to update my JVM to 64 bit and getting it to work fine.