ImageJ - How to create a fat Plugin.jar with Maven that includes dependencies.

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How to create a fat Plugin.jar with Maven that includes dependencies.

Posted by Michael P Ellis on Nov 04, 2020; 4:19pm
URL: http://imagej.273.s1.nabble.com/How-to-create-a-fat-Plugin-jar-with-Maven-that-includes-dependencies-tp5024146.html

I am trying to create an ImageJ (1) plugin with maven. There is a dependency (log4J) and I am using the maven maven-shade-plugin to create a plugin with the intention that the plugin will be self-contained and include the necessary dependencies.

So far I have found that when this plugin is installed into a standard ImageJ installation and run from the command line (OS-X) with java -jar in,jar it fails with an error message indicating that it has been unable to locate the log4j libraries.

Manually installing copes of the log4j libraries in the ImageJ plugins/jar directory allows the plugin to run successfully and I get to see the log output on the terminal/

I have created a SSCCE to demonstrate which can be seen here: https://gitlab.com/Michael51773/minimalimagejplugin (https://gitlab.com/Michael51773/minimalimagejplugin)

I am not that experienced with maven so if the solution is maven related please assume I have the experience of a small child!

The ultimate use scenario will include a multitude of dependencies and not just the log4j.

I hope to release some of the plugins I am using for general public use and to be free of charge (so hope to put something back into the community)

Many thanks in anticipation of any help.

--- MinimalImageJPlugin_.jar ---
import ij.IJ;
import ij.plugin.PlugIn;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class MinimalImageJPlugin_ implements PlugIn {
private static final Logger LOGGER = LogManager.getLogger();

@Override
public void run(String arg) {
LOGGER.error("Hello");
IJ.showMessage(String.format("MinimalImageJPlugin_ arg="%s"", arg));
}
}

--- pom.xml ---
<?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>biz.dsuk</groupId>
<artifactId>MinimalImageJPlugin__</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>MinimalImageJ</name>
<description>A minimal ImageJ PlugIn build with a maven with a dependency
on log4j to work out how to build a fat or uber jar that includes the
log4j jar dependency and can still be used as an ImageJ Plugin.</description>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>14</maven.compiler.source>
<maven.compiler.target>14</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>net.imagej</groupId>
<artifactId>ij</artifactId>
<version>1.53e (DS)</version>
</dependency>

<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.13.3</version>
<scope>compile</scope>
<type>jar</type>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.13.3</version>
<scope>compile</scope>
<type>jar</type>
</dependency>
</dependencies>
<build>
<finalName>SC4_</finalName>
<plugins>
<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>
<configuration>
<artifactSet>
<excludes>
<exclude>net.imagej:ij</exclude>
</excludes>
</artifactSet>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>

--- END ---

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