Kotlin ending up in the jar file

[Antoine Apollis]

Hello,

I recently started a Javalin project in Java, with this simple 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 https://maven.apache.org/xsd/maven-4.0.0.xsd"
>
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.company</groupId>
    <artifactId>test</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>Test</name>
    <description>Test</description>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.16.1</version>
        </dependency>
        <dependency>
            <groupId>io.javalin</groupId>
            <artifactId>javalin</artifactId>
            <version>6.1.3</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>2.0.10</version>
        </dependency>
        <dependency>
            <groupId>io.javalin</groupId>
            <artifactId>javalin-testtools</artifactId>
            <version>6.1.3</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter</artifactId>
            <version>5.10.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.13.0</version>
                <configuration>
                    <release>21</release>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <version>3.7.1</version>
                <configuration>
                    <finalName>test</finalName>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                    <archive>
                        <manifest>
                            <mainClass>
                                com.company.test.TestApplication
                            </mainClass>
                        </manifest>
                    </archive>
                </configuration>
                <executions>
                    <execution>
                        <id>make-assembly</id>
                        <phase>package</phase>
                        <goals><goal>single</goal></goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

When I run mvnw clean install, I end up with an executable jar, which runs fine. What worries me is that if I look inside, I have a kotlin folder which takes the majority of the space, but I never use Kotlin in my project. Is this normal? Should I exclude something?

[David]

Is this normal? Should I exclude something?

It's normal. Kotlin is included as a dependency in Javalin, similar to a utility artifact like Guava. Javalin will not work if you exclude it.

[Antoine Apollis]

Thanks a lot!

[Alberto Zugazagoitia]

Using Kotlin is very nice, you could give it a try 😄