MapDB ClassNotFoundException: kotlin.jvm.internal.

问题:

I am trying to run a simple mapdb example, but get the error:

    Exception in thread "main" java.lang.NoClassDefFoundError: kotlin/jvm/internal/Intrinsics
    at org.mapdb.DBMaker.fileDB(DBMaker.kt)
    at leechies.Truc.main(Truc.java:9)
Caused by: java.lang.ClassNotFoundException: kotlin.jvm.internal.Intrinsics
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 2 more

My class:

package leechies;
import java.util.concurrent.ConcurrentMap;

import org.mapdb.DB;
import org.mapdb.DBMaker;

public class Truc {
    public static void main(String[] args) {
        DB db = DBMaker.fileDB("file.db").make();
        ConcurrentMap map = db.hashMap("map").createOrOpen();
        map.put("something", "here");
        db.close();
    }
}

My pomx.xml

<dependencies>
    <dependency>
        <groupId>org.mapdb</groupId>
        <artifactId>mapdb</artifactId>
        <version>3.0.3</version>
    </dependency>

I run with rigth click -> Run as... -> java application.

回答1:

Either kotlin-runtime has to be in classpath and verify with $ echo $CLASSPATH.

Or you have to add kotlin-runtime to maven and then assemble inside the jar itself with mvn compile assembly:single,

<dependency>
    <groupId>org.jetbrains.kotlin</groupId>
    <artifactId>kotlin-runtime</artifactId>
    <version>1.1.3</version>
    <scope>compile</scope>
</dependency>

<dependency>
    <groupId>org.jetbrains.kotlin</groupId>
    <artifactId>kotlin-stdlib</artifactId>
    <version>1.1.3</version>
    <scope>compile</scope>
</dependency>

which need to be attached to artifact as well and can be done with assembly-plugin.

    <plugin>
        <artifactId>maven-assembly-plugin</artifactId>
        <configuration>
            <archive>
                <manifest>
                    <mainClass>event.handlers.InventoryEventHandler</mainClass>
                </manifest>
            </archive>
            <descriptorRefs>
                <descriptorRef>jar-with-dependencies</descriptorRef>
            </descriptorRefs>
        </configuration>
    </plugin>

you can verify the kotlin-runtime is added to jar by

$ jar -tf target/amz-wavelength-1.0-SNAPSHOT-jar-with-dependencies.jar | grep kotlin-runtime
META-INF/kotlin-runtime.kotlin_module

or

$ jar -tf target/amz-wavelength-1.0-SNAPSHOT-jar-with-dependencies.jar | grep "kotlin/jvm/internal/*"

回答2:

It will fail because you do not have the necessary kotlin runtime jar in your classpath. You have to run some command to resolve this error. please refer this link for commands:-

https://dzone.com/articles/exercises-in-kotlin-part-1-getting-started

回答3:

@prayagupd's answer works for me. But I thought it worth mentioning that another option is to use the maven-shade-plugin instead of the maven-assembly-plugin (put this in the build/plugins section of your pom.xml file):

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <version>2.4.3</version>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>shade</goal>
            </goals>
        </execution>
    </executions>
</plugin>

The shade plugin is nice because it allows you to exclude duplicate classes. If you have to use either plugin, it's good to know you don't need both. Build time and resulting jar file sizes are nearly identical in my quick tests, but the assembly plugin (that prayagupd suggested) doesn't add a bunch of warnings to my build output, so I'm going with that.

回答4:

Maybe run your class from maven, it will add all necessary dependencies.

run main class of Maven project