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>
    
    <!-- Project information -->
    <groupId>dev._2lstudios</groupId>
    <artifactId>ExamplePlugin</artifactId>
    <packaging>jar</packaging>

    <!-- Plugin Information -->
    <name>ExamplePlugin</name>
    <description>This is just an example plugin</description>
    <version>0.0.1</version>
    <url>https://github.com/2lstudios-mc/bukkit-boilerplate</url>

    <properties>
        <author>2LStudios</author>
        <mainClass>dev._2lstudios.example.ExamplePlugin</mainClass>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

   <!-- External repositories -->
    <repositories>
        <repository>
            <id>spigot-repo</id>
            <url>https://hub.spigotmc.org/nexus/content/repositories/snapshots/</url>
        </repository>
    </repositories>

    <!-- Dependencies imports -->
    <dependencies>
        <dependency>
            <groupId>org.spigotmc</groupId>
            <artifactId>spigot-api</artifactId>
            <version>1.18.1-R0.1-SNAPSHOT</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <!-- Build settings -->
    <build>
        <!-- Name of your compiled artifact -->
        <finalName>${artifactId}</finalName>
        <!-- Directory of .java files -->
        <sourceDirectory>src/main/java</sourceDirectory>
        <!-- Clean old builds and install dependencies before compile -->
        <defaultGoal>clean install</defaultGoal>
        <!-- Package files inside resource directory in to the jar -->
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <filtering>true</filtering>
                <excludes>
                    <exclude>**/*.java</exclude>
                </excludes>
            </resource>
        </resources>

        <!-- Compilation settings starts here -->
        <plugins>
            <!-- Compile with java 8 -->
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <!-- Include dependencies inside jar -->
            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <version>3.3.0</version>
                <configuration>
                    <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>
</project>