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Separate build step for Java file - Maven

Within a larger Maven project, I have a Java file (AudioFileBuilder.java) that generates audio files from the Google Cloud Text-to-Speech service. It can execute from its own main() class; however, this file references an enumeration within the project (that other project source files depend on).
I am creating a fat JAR (JAR-with-dependencies), .exe file (Windows), and .app file (macOS) for the main project. I would like to exclude the AudioFileBuilder.java file AND the associated Google Cloud Text-to-Speech dependency in the JAR, exe, and app files. However, I still need the AudioFileBuilder.java file to run every time the project is built.
Here is a link to my project's current POM file (the project is open-source):
https://github.com/hadi16/GamesForTheBlind/blob/Alex-Branch/pom.xml
This is my current POM file:
<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>edu.up</groupId>
<artifactId>Games_For_Blind</artifactId>
<version>1.0.0.0</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<packaging>jar</packaging>
<dependencies>
<!-- Compile Dependencies -->
<dependency>
<groupId>com.google.cloud</groupId>
<artifactId>google-cloud-texttospeech</artifactId>
<version>0.117.0-beta</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>javax.xml.bind</groupId>
<artifactId>jaxb-api</artifactId>
<version>2.3.1</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.glassfish.jaxb</groupId>
<artifactId>jaxb-runtime</artifactId>
<version>2.3.2</version>
<scope>compile</scope>
</dependency>
<!-- Test Dependencies -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.2</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>12</source>
<target>12</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.1.1</version>
<configuration>
<outputDirectory>${project.build.directory}/dist</outputDirectory>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>gamesforblind.Main</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>assemble-all</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.1.0</version>
<executions>
<execution>
<id>copy-resources</id>
<phase>process-classes</phase>
<goals>
<goal>copy-resources</goal>
</goals>
<configuration>
<outputDirectory>${project.build.outputDirectory}</outputDirectory>
<resources>
<resource>
<directory>${basedir}/target/xsd-out</directory>
<filtering>false</filtering>
</resource>
</resources>
</configuration>
</execution>
</executions>
</plugin>
<!-- To generate the phrase audio files. -->
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.6.0</version>
<executions>
<execution>
<phase>prepare-package</phase>
<goals>
<goal>exec</goal>
</goals>
</execution>
</executions>
<configuration>
<executable>java</executable>
<arguments>
<argument>-classpath</argument>
<classpath/>
<argument>gamesforblind.synthesizer.AudioFileBuilder</argument>
</arguments>
<environmentVariables>
<GOOGLE_APPLICATION_CREDENTIALS>google_api_key.json</GOOGLE_APPLICATION_CREDENTIALS>
</environmentVariables>
</configuration>
</plugin>
<!-- Create executable Windows file. -->
<plugin>
<groupId>com.akathist.maven.plugins.launch4j</groupId>
<artifactId>launch4j-maven-plugin</artifactId>
<version>1.7.25</version>
<executions>
<execution>
<id>l4j-clui</id>
<phase>package</phase>
<goals>
<goal>launch4j</goal>
</goals>
<configuration>
<headerType>gui</headerType>
<jar>${project.build.directory}/dist/${project.artifactId}-${project.version}-jar-with-dependencies.jar</jar>
<outfile>${project.build.directory}/dist/${project.artifactId}-${project.version}.exe</outfile>
<classPath>
<mainClass>gamesforblind.Main</mainClass>
</classPath>
<jre>
<minVersion>12</minVersion>
<jdkPreference>preferJre</jdkPreference>
</jre>
<versionInfo>
<copyright>2019</copyright>
<fileVersion>${project.version}</fileVersion>
<txtFileVersion>${project.version}</txtFileVersion>
<fileDescription>${project.name}</fileDescription>
<productVersion>${project.version}</productVersion>
<txtProductVersion>${project.version}</txtProductVersion>
<productName>${project.name}</productName>
<internalName>${project.name}</internalName>
<originalFilename>${project.artifactId}-${project.version}.exe</originalFilename>
<companyName>University of Portland</companyName>
</versionInfo>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>de.perdian.maven.plugins</groupId>
<artifactId>macosappbundler-maven-plugin</artifactId>
<version>1.3.0</version>
<configuration>
<plist>
<CFBundleDisplayName>Games For The Blind</CFBundleDisplayName>
<JVMMainClassName>gamesforblind.Main</JVMMainClassName>
<JVMVersion>12</JVMVersion>
<CFBundleDisplayName>Games For The Blind</CFBundleDisplayName>
<CFBundleName>Games For The Blind</CFBundleName>
</plist>
</configuration>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>bundle</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
UPDATE:
I divided the project into two separate modules: "audio-builder" & "application" - as suggested by Welsh.
However, I have a Java enumeration ("Phrases.java") that both the audio-builder & application uses. The audio-builder needs this file to know which audio phrases are currently in the program, while the rest of the application needs this to load in said audio files & call the playback of these files.
So, this made me add the "audio-builder" module as a dependency for the "application" module. Since the Google Cloud dependency is needed at compile-time, this means that it is bundled in the generated JAR, app, and exe files.
These changes can be found here: https://github.com/hadi16/GamesForTheBlind/tree/Maven-Fixes
Root POM file:
<?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>edu.up</groupId>
<artifactId>games-for-the-blind</artifactId>
<version>1.0.0.0</version>
<modules>
<module>games-for-the-blind/audio-builder</module>
<module>games-for-the-blind/application</module>
</modules>
<packaging>pom</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
</project>
Audio-builder POM file:
<?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>edu.up</groupId>
<artifactId>audio-builder</artifactId>
<version>1.0.0.0</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>com.google.cloud</groupId>
<artifactId>google-cloud-texttospeech</artifactId>
<version>0.117.0-beta</version>
<scope>compile</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>12</source>
<target>12</target>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.6.0</version>
<executions>
<execution>
<phase>prepare-package</phase>
<goals>
<goal>exec</goal>
</goals>
</execution>
</executions>
<configuration>
<executable>java</executable>
<arguments>
<argument>-classpath</argument>
<classpath/>
<argument>builder.AudioFileBuilder</argument>
</arguments>
<environmentVariables>
<GOOGLE_APPLICATION_CREDENTIALS>google_api_key.json</GOOGLE_APPLICATION_CREDENTIALS>
</environmentVariables>
</configuration>
</plugin>
</plugins>
</build>
</project>
Application POM file (note the dependency to audio-builder):
<?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>edu.up</groupId>
<artifactId>application</artifactId>
<version>1.0.0.0</version>
<packaging>jar</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<!-- Compile Dependencies -->
<dependency>
<groupId>javax.xml.bind</groupId>
<artifactId>jaxb-api</artifactId>
<version>2.3.1</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.glassfish.jaxb</groupId>
<artifactId>jaxb-runtime</artifactId>
<version>2.3.2</version>
<scope>compile</scope>
</dependency>
<!-- Test Dependencies -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>edu.up</groupId>
<artifactId>audio-builder</artifactId>
<version>1.0.0.0</version>
<scope>compile</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.2</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>12</source>
<target>12</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.1.1</version>
<configuration>
<outputDirectory>${project.build.directory}/dist</outputDirectory>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>gamesforblind.Main</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>assemble-all</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.1.0</version>
<executions>
<execution>
<id>copy-resources</id>
<phase>process-classes</phase>
<goals>
<goal>copy-resources</goal>
</goals>
<configuration>
<outputDirectory>${project.build.outputDirectory}</outputDirectory>
<resources>
<resource>
<directory>${basedir}/target/xsd-out</directory>
<filtering>false</filtering>
</resource>
</resources>
</configuration>
</execution>
</executions>
</plugin>
<!-- Create executable Windows file. -->
<plugin>
<groupId>com.akathist.maven.plugins.launch4j</groupId>
<artifactId>launch4j-maven-plugin</artifactId>
<version>1.7.25</version>
<executions>
<execution>
<id>l4j-clui</id>
<phase>package</phase>
<goals>
<goal>launch4j</goal>
</goals>
<configuration>
<headerType>gui</headerType>
<jar>
${project.build.directory}/dist/${project.artifactId}-${project.version}-jar-with-dependencies.jar
</jar>
<outfile>${project.build.directory}/dist/${project.artifactId}-${project.version}.exe
</outfile>
<classPath>
<mainClass>gamesforblind.Main</mainClass>
</classPath>
<jre>
<minVersion>12</minVersion>
<jdkPreference>preferJre</jdkPreference>
</jre>
<versionInfo>
<copyright>2019</copyright>
<fileVersion>${project.version}</fileVersion>
<txtFileVersion>${project.version}</txtFileVersion>
<fileDescription>${project.name}</fileDescription>
<productVersion>${project.version}</productVersion>
<txtProductVersion>${project.version}</txtProductVersion>
<productName>${project.name}</productName>
<internalName>${project.name}</internalName>
<originalFilename>${project.artifactId}-${project.version}.exe</originalFilename>
<companyName>University of Portland</companyName>
</versionInfo>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>de.perdian.maven.plugins</groupId>
<artifactId>macosappbundler-maven-plugin</artifactId>
<version>1.3.0</version>
<configuration>
<plist>
<CFBundleDisplayName>Games For The Blind</CFBundleDisplayName>
<JVMMainClassName>gamesforblind.Main</JVMMainClassName>
<JVMVersion>12</JVMVersion>
<CFBundleDisplayName>Games For The Blind</CFBundleDisplayName>
<CFBundleName>Games For The Blind</CFBundleName>
</plist>
</configuration>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>bundle</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
Thank you!

I would recommend that you split your projects into two sub projects, so you would have for example:
games-for-the-blind/
pom.xml
audio-builder/
pom.xml
application/
pom.xml
Then what you can do is have the audio-builder package output the required files into the application/resources directory and have it listed first in the main pom.xml file.
This would allow you to distribute the application resultant files that would not contain any of the details of the audio-builder project.

java.lang.NoClassDefFoundError while using maven eclipse AsciidoctorJ

I'm trying to use Asciidoctor to generate an html file using the method built in asciidocj (convertFile)
I'm getting java.lang.NoClassDefFoundError:org/asciidoctor/OptionsBuilder
I'm working on eclipse ; maven and
I added the Asciidoctor dependency in the pom.xml file.
public void view(String document) {
OptionsBuilder op = OptionsBuilder.options().toFile(false);
Asciidoctor asciidoctor = create();
String html = asciidoctor.convertFile(new File(this.path + "/" + document + ".adoc"), op.asMap());
System.out.println(html);
}
<?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>ProgGl</groupId>
<artifactId>PriseDeNotes</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>PriseDeNotes</name>
<description>Projet de Prog Gl</description>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<main-class>ProgGl.PriseDeNote.App</main-class>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
<configuration>
<archive>
<manifest>
<mainClass>${main-class}</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.asciidoctor</groupId>
<artifactId>asciidoctor-maven-plugin</artifactId>
<version>1.5.6</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-site-plugin</artifactId>
<version>3.3</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-project-info-reports-plugin</artifactId>
<version>2.7</version>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.1.0</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>${main-class}</mainClass>
</manifest>
</archive>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-source-plugin</artifactId>
<version>3.0.1</version>
<executions>
<execution>
<id>attach-sources</id>
<phase>package</phase>
<goals>
<goal>jar-no-fork</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-javadoc-plugin</artifactId>
<version>3.0.0-M1</version>
<executions>
<execution>
<id>attach-javadocs</id>
<phase>package</phase>
<goals>
<goal>jar</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>com.github.spotbugs</groupId>
<artifactId>spotbugs-maven-plugin</artifactId>
<version>3.1.7</version>
<dependencies>
<!-- overwrite dependency on spotbugs if you want to specify the version of spotbugs -->
<dependency>
<groupId>com.github.spotbugs</groupId>
<artifactId>spotbugs</artifactId>
<version>3.1.8</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
<reporting>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
<version>3.0.0</version>
<reportSets>
<reportSet>
<reports>
<report>checkstyle</report>
</reports>
</reportSet>
</reportSets>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jxr-plugin</artifactId>
<version>2.3</version>
</plugin>
</plugins>
</reporting>
<dependencies>
<dependency>
<groupId>org.asciidoctor</groupId>
<artifactId>asciidoctorj</artifactId>
<version>2.0.0</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.hamcrest</groupId>
<artifactId>hamcrest-all</artifactId>
<version>1.3</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
mvn install, package everything is working fine,
when I execute the program I'm getting this error.
I read that it's about class path etc... but I don't understand how to do otherwise
Exception in thread "main" java.lang.NoClassDefFoundError: org/asciidoctor/OptionsBuilder
at ProgGl.PriseDeNote.Application.view(Application.java:171)
at ProgGl.PriseDeNote.Commands.ViewCommand.execute(ViewCommand.java:22)
at ProgGl.PriseDeNote.App.main(App.java:66)
Caused by: java.lang.ClassNotFoundException: org.asciidoctor.OptionsBuilder
at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 3 more
Thank you.

General, the maven assembly plugin generates another .jar called target/PriseDeNotes-0.0.1-SNAPSHOT-jar-with-dependencies.jar.
You can try java -jar target/PriseDeNotes-0.0.1-SNAPSHOT-jar-with-dependencies.jar to run the application.

I see you have the maven-assembly-plugin already. Compile with mvn clean compile assembly:single then run with java -jar target/PriseDeNotes-0.0.1-SNAPSHOT-jar-with-dependencies.jar.

I think the problem is, that maven doesn't copy the dependencies into the jar. Try to copy the dependencies in the target with the related plugin you can find here:
https://maven.apache.org/plugins/maven-dependency-plugin/examples/copying-project-dependencies.html
With this, it should copy the needed dependencies to the target folder.

How to create a fat jar?

With SpringBoot, you have the #SpringBootApplication annotation, but what is the equivalent with the neat Java Spark framework?
IntelliJ creates a Maven project and I added the spark dependency, but running the install goal, I get a 5 KB jar with no manifest. Not an executable jar.
The pom.xml created thus far is as follows:
<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>sparkdemo</groupId>
<artifactId>sparkdemo</artifactId>
<version>1.0 </version>
<packaging>jar</packaging>
<name>sparkdemo</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.sparkjava</groupId>
<artifactId>spark-core</artifactId>
<version>2.5.4</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
<optimize>true</optimize>
<debug>true</debug>
</configuration>
</plugin>
</plugins>
</build>
</project>
Would appreciate any suggestions....Thanks!

What you need here is an executable jar that will not only contain your classes, but also classes from all your dependencies.
For that you can use the Maven Assembly Plugin.
See the sample code below.
<project>
[...]
<build>
[...]
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>org.sample.App</mainClass> // specify your main class here
</manifest>
</archive>
</configuration>
<executions>
<execution>
<id>make-assembly</id> <!-- this is used for inheritance merges -->
<phase>package</phase> <!-- bind to the packaging phase -->
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
[...]
</project>
Then, run mvn package and the executable jar should be located in the folder target (with a name like ProjectName-1.0-SNAPSHOT-jar-with-dependencies.jar).

Looks like you are looking for maven assembly plugin
Add this in the plugin section and run mvn package
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>assemble-all</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>

Java on Heroku can't find Main.class

I am trying to get a very simple Spark app running on Heroku. It runs fine locally. I suspect it's some subtle Maven problem because I've used some Maven scripts from Heroku that I don't quite understand.
Here's my pom.xml:
<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>SparkDemo</groupId>
<artifactId>SparkDemo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<build>
<sourceDirectory>src</sourceDirectory>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<descriptorRefs>
<!-- This tells Maven to include all dependencies -->
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>Main</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>com.heroku.sdk</groupId>
<artifactId>heroku-maven-plugin</artifactId>
<version>0.4.4</version>
<configuration>
<jdkVersion>1.8</jdkVersion>
<!-- Use your own application name -->
<appName>still-journey-10861</appName>
<processTypes>
<!-- Tell Heroku how to launch your application -->
<!-- You might have to remove the ./ in front -->
<web>java -jar target/SparkDemo-0.0.1-SNAPSHOT-jar-with-dependencies.jar</web>
</processTypes>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>com.sparkjava</groupId>
<artifactId>spark-core</artifactId>
<version>2.3</version>
</dependency>
<dependency>
<groupId>com.j2html</groupId>
<artifactId>j2html</artifactId>
<version>0.5.0</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-csv</artifactId>
<version>1.2</version>
</dependency>
</dependencies>
</project>
When I look inside the Jar on Heroku, I see the relevant class right there:
~ $ jar tf target/SparkDemo-0.0.1-SNAPSHOT.jar
META-INF/
META-INF/MANIFEST.MF
edu/
edu/brandeis/
edu/brandeis/cosi12b/
edu/brandeis/cosi12b/sparkdemo/
edu/brandeis/cosi12b/sparkdemo/Main.class
edu/brandeis/cosi12b/sparkdemo/StudentChooserServer.class
edu/brandeis/cosi12b/sparkdemo/StudentDirectory.class
edu/brandeis/cosi12b/sparkdemo/StudentInfo.class
studentnames.csv
META-INF/maven/
META-INF/maven/SparkDemo/
META-INF/maven/SparkDemo/SparkDemo/
META-INF/maven/SparkDemo/SparkDemo/pom.xml
META-INF/maven/SparkDemo/SparkDemo/pom.properties

The class name should be complete, with the package too. So instead of <mainClass>Main</mainClass> it should be <mainClass>edu.brandeis.cosi12b.sparkdemo.Main</mainClass>.

creating a jar-with-dependencies

I am creating a jar-with-dependencies in mvn 3.0.3. I have successfully done this in one project (using just mvn install) and created a complete jar-wth-dependencies. I copied the relevant chunk of POM code (<plugins>...</plugins>, which someone else wrote!) to the current project (which differs in that it has assemblies). It creates the normal snapshot jar (jumbo-converters-compchem-gaussian-0.3-SNAPSHOT.jar) but no jar-with-dependencies. How should I amend the POM?
<?xml version="1.0" encoding="UTF-8"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>cml</groupId>
<artifactId>jumbo-converters</artifactId>
<version>0.3-SNAPSHOT</version>
<relativePath>../../pom.xml</relativePath>
</parent>
<artifactId>jumbo-converters-compchem-gaussian</artifactId>
<name>jumbo-converters-compchem-gaussian</name>
<dependencies>
<dependency>
<groupId>${jumbo.groupId}</groupId>
<artifactId>jumbo</artifactId>
</dependency>
<dependency>
<groupId>cml</groupId>
<artifactId>jumbo-converters-core</artifactId>
</dependency>
<dependency>
<groupId>cml</groupId>
<artifactId>jumbo-converters-compchem-common</artifactId>
<version>0.3-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>cml</groupId>
<artifactId>jumbo-converters-templates</artifactId>
<version>0.3-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>cml</groupId>
<artifactId>jumbo-converters-testutils</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>cml</groupId>
<artifactId>jumbo-converters-compchem-testutils</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>org.xmlcml.cml.converters.compchem.gaussian.GaussianLogXML2CompchemConverter</mainClass>
</manifest>
</archive>
<excludes>
<exclude>.hgsub</exclude>
<exclude>**/.hg/</exclude>
<exclude>**/.project</exclude>
<exclude>**/external/</exclude>
</excludes>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>org.xmlcml.cml.converters.compchem.gaussian.GaussianLogXML2CompchemConverter</mainClass>
</manifest>
</archive>
<excludes>
<exclude>.hgsub</exclude>
<exclude>**/.hg/</exclude>
<exclude>**/.project</exclude>
<exclude>**/external/</exclude>
</excludes>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>

First,
Use maven dependency plugin to retrieve/store the dependencies (more info here) to your project folder.
Ex: Say lib folder.
Now mark this lib folder as a "Resources" folder.
Like,
<resources>
<resource>
<directory>lib</directory>
<targetPath>lib</targetPath>
</resource>
</resources>
Now mvn install should include the dependencies in your final artifact.
(copying Shinchan's comment to here so it can be formatted:
Simple add this to ur pom.
<build>
<resources>
<resource>
<directory>lib</directory>
<targetPath>lib</targetPath>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.8</version>
<executions>
<execution>
<phase>install</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>lib</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>