NoClassDefFoundError of com/fasterxml/jackson/databind/ObjectMapper with Maven

Question

This is a similar question as the one here, which is unfortunately unresolved yet.

If you want to debug the code, here is the GitHub repo.

I got the following NoClassDefFoundError for ObjectMapper though I have added the related dependency to Mave pom.xml.

Exception in thread "main" java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/ObjectMapper
    at demo.DemoMain.main(DemoMain.java:10)
Caused by: java.lang.ClassNotFoundException: com.fasterxml.jackson.databind.ObjectMapper
    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)
    ... 1 more

Here is the source code DemoMain.java

package demo;

import com.fasterxml.jackson.databind.ObjectMapper;

public class DemoMain {
    public static void main(String[] args) {
        System.out.println("Start");
        ObjectMapper mapper = new ObjectMapper();
        System.out.println("End");
    }
}

This is my 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>com.example</groupId>
<artifactId>Demo</artifactId>
<version>1.0-SNAPSHOT</version>

<dependencies>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-annotations</artifactId>
        <version>2.8.3</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.8.3</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.8.3</version>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>3.0.0</version>
            <configuration>
                <archive>
                    <index>true</index>
                    <manifest>
                        <addClasspath>true</addClasspath>
                        <mainClass>demo.DemoMain</mainClass>
                    </manifest>
                </archive>
            </configuration>
        </plugin>
    </plugins>
</build>

I compile and run the app by

mvn clean install
java -jar target/Demo-1.0-SNAPSHOT.jar

It's too weird! Maven build successful mean that your code is not having any problem. Did you try to build it using an IDE? — TuyenNTA, May 07 '17 at 00:59
@TuyenNguyen I'm confused too. Here is the source code repository. https://github.com/hackjutsu/StackOverflow-Maven-Jackson — hackjutsu, May 07 '17 at 01:01
you should try to using an IDE to build and run your code. I have tested your code, it run fine! — TuyenNTA, May 07 '17 at 01:07
Thanks for trying:) Yes, I just tried using IntelliJ and it worked fine. But an IDE shouldn't be a prerequisite for a Java application... Is it because I miss some flags when launching the jar? — hackjutsu, May 07 '17 at 01:13
I just figure out that `mvn clean install` does not create any .jar file. So what .jar file you are running on? — TuyenNTA, May 07 '17 at 01:28
En.. Interesting, it should create a jar file `target/Demo-1.0-SNAPSHOT.jar`. Anyway, I figure out the issue. The maven plugin I was using doesn't build a fat jar that comes with dependencies. To run the jar with `java -jar`, we can use `maven-assembly-plugin` instead, which bundles the jar with its dependencies. By the way, the reason why an IDE works is because it adds the classpath flag automatically when running the app. Thanks for helping me troubleshoot. — hackjutsu, May 07 '17 at 01:48

score 11 · Answer 1 · answered May 07 '17 at 06:16

11

<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
<version>2.8.5</version>
</dependency>

answered May 07 '17 at 06:16

kiranbirajdar

195
2
12

try this dependancy – kiranbirajdar May 07 '17 at 06:16
15

You should add an actual explanation in your answer, otherwise, it's just you pasting some code which the poster might not understand. – carlspring May 09 '17 at 12:31

score 10 · Accepted Answer · edited May 23 '17 at 12:34

As I answered here

The default maven plugin doesn't build a fat jar with dependencies.

To build a jar bundled with its dependencies so that we can execute it with java -jar, we can use maven-assembly-plugin, which packages the jar with the name xxx-jar-with-dependencies.jar.

Here is a sample pom.xml

<build>
    <plugins>
        <plugin>
            <artifactId>maven-assembly-plugin</artifactId>
            <version>3.0.0</version>
            <configuration>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
                <archive>
                    <manifest>
                        <mainClass>com.example.yourMain</mainClass>
                    </manifest>
                </archive>
            </configuration>
            <executions>
                <execution>
                    <id>make-assembly</id> <!-- this is used for inheritance merges -->
                    <phase>package</phase> <!-- bind to the packaging phase -->
                    <goals>
                        <goal>single</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

Now you should be able to run your jar with

java -jar xxx-jar-with-dependencies.jar

NoClassDefFoundError of com/fasterxml/jackson/databind/ObjectMapper with Maven

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