CODEWITHSUNDEEP
javamavennoclassdeffounderrorjackson-databind
ZamenWolk
ZamenWolk

Reputation: 125

Jackson databind working in IDE environment but not in jar

I am trying to use jackson databind using Maven. It works fine in my IDE environment (I'm using IntelliJ IDEA), but when I try to make a jar with it, it produces an error on startup and instantly crashes. Specifically, the error is this :

java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonFactory

This is specific to the JAR, and I don't know why it does that at all. What did I do wrong ?

Here is the 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>me.zam</groupId>
    <artifactId>jackson</artifactId>
    <version>1.0-SNAPSHOT</version>

    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.2.3</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.dataformat</groupId>
            <artifactId>jackson-dataformat-yaml</artifactId>
            <version>2.3.0</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <!-- Make this jar executable -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <configuration>
                    <archive>
                        <manifest>
                            <!-- Jar file entry point -->
                            <mainClass>me.Main</mainClass>
                            <addClasspath>true</addClasspath>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

And here is the Main object

package me;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.File;

/**
 * Created by Martin on 31/03/2017.
 */
public class Main
{
    public static void main(String[] args)
    {
        ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
        try {
            User user = mapper.readValue(new File("user.yaml"), User.class);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Upvotes: 3

Views: 1385

Answers (3)

Amit
Amit

Reputation: 32376

So I just tried it in my system and was able to reproduce the issue.

To solve it you need to add one more plugin maven-shade-plugin, which is required to create the fat jar, i.e. Jar with all the required dependency.

Update pom.xml file, note here I've renamed the class which contains main method to Test and put into the default package:-

 <?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>com.so</groupId>
        <artifactId>jackson</artifactId>
        <version>1.0-SNAPSHOT</version>

        <packaging>jar</packaging>

        <properties>
            <mainClass>Test</mainClass>
        </properties>

        <dependencies>
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-databind</artifactId>
                <version>2.2.3</version>
            </dependency>
            <dependency>
                <groupId>com.fasterxml.jackson.dataformat</groupId>
                <artifactId>jackson-dataformat-yaml</artifactId>
                <version>2.3.0</version>
            </dependency>
        </dependencies>

        <build>
            <plugins>
                <plugin>
                    <artifactId>maven-shade-plugin</artifactId>
                    <version>2.4.1</version>
                    <configuration>
                        <createDependencyReducedPom>true</createDependencyReducedPom>
                        <transformers>
                            <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
                            <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                <mainClass>${mainClass}</mainClass>
                            </transformer>
                        </transformers>
                        <!-- exclude signed Manifests -->
                        <filters>
                            <filter>
                                <artifact>*:*</artifact>
                                <excludes>
                                    <exclude>META-INF/*.SF</exclude>
                                    <exclude>META-INF/*.DSA</exclude>
                                    <exclude>META-INF/*.RSA</exclude>
                                </excludes>
                            </filter>
                        </filters>
                    </configuration>
                    <executions>
                        <execution>
                            <phase>package</phase>
                            <goals>
                                <goal>shade</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
                <!-- Make this jar executable -->
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-jar-plugin</artifactId>
                    <configuration>
                        <archive>
                            <manifest>
                                <!-- Jar file entry point -->
                                <mainClass>Test</mainClass>
                                <addClasspath>true</addClasspath>
                            </manifest>
                        </archive>
                    </configuration>
                </plugin>
            </plugins>
        </build>

    </project>

Once done, I ran the code by running first mvn clean package command, which creates the fat jar and then run the code by java -cp target/jackson-1.0-SNAPSHOT.jar Test command.

Let me know if you face any issue running the code.

Upvotes: 1

Master Po
Master Po

Reputation: 1697

Can you please check whether the generated jar contains the specified dependencies such as jackson-databind and jackson-dataformat-yaml? I'm not sure the jar plugin exports the maven dependencies. I normally use maven assembly plugin or shade plugin to generate jar with dependencies.

Upvotes: 1

ramidzkh
ramidzkh

Reputation: 11

I'm not sure but you need to change <mainClass> to <MainClass> and set the scope for the dependency to compile like <scope>compile</scope> to add it directly to the jar file.

Upvotes: 0

Related Questions