NoClassDefFoundError as I run a Maven packaged JAR file

Question

I am using Maven to compile and package a Java application from the command line:

mvn clean
mvn compile
mvn package

These commands run without a problem. But when I try to run the generated JAR file

java -jar target/JarFile.jar

I get the following error:

Error: Unable to initialize main class com.company.Main
Caused by: java.lang.NoClassDefFoundError: com/google/api/client/json/JsonFactory

Which is a class from an external dependency. These dependencies are also managed by Maven (i.e., I am not supplying them locally, but listing them in my POM file.) Since I am able to run the application inside the IDE, I assume I am missing a step to make the dependencies available to the JAR file. Here is my 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>

    <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <groupId>test-maven-project</groupId>
    <artifactId>test</artifactId>
    <version>1.0</version>

    <dependencies>
        <dependency>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
        </dependency>
        <dependency>
            <groupId>com.google.oauth-client</groupId>
            <artifactId>google-oauth-client</artifactId>
            <version>1.30.6</version>
        </dependency>
        <dependency>
            <groupId>com.google.http-client</groupId>
            <artifactId>google-http-client</artifactId>
            <version>1.34.2</version>
        </dependency>
        <dependency>
            <groupId>com.google.api-client</groupId>
            <artifactId>google-api-client</artifactId>
            <version>1.30.9</version>
        </dependency>
        <dependency>
            <groupId>com.google.http-client</groupId>
            <artifactId>google-http-client-jackson2</artifactId>
            <version>1.34.2</version>
        </dependency>
        <dependency>
            <groupId>com.google.apis</groupId>
            <artifactId>google-api-services-customsearch</artifactId>
            <version>v1-rev20200401-1.30.9</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <!-- Build an executable JAR -->
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.1.0</version>
                <configuration>
                    <archive>
                        <manifest>
                            <addClasspath>true</addClasspath>
                            <classpathPrefix>lib/</classpathPrefix>
                            <mainClass>com.company.Main</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Could you point me in the right direction so that the dependencies are accessible at runtime?

score 1 · Accepted Answer · answered Apr 10 '20 at 07:34

1

To run your jar from commandline, you must either explicitly specify the classpath on the command line or build an executable jar:

How can I create an executable JAR with dependencies using Maven?

BTW: mvn package already executes mvn compile, so you need not call mvn compile explicitly.

answered Apr 10 '20 at 07:34

J Fabian Meier

33,516
10
64
142

Building a JAR with dependencies with the maven-assembly-plugin as indicated in the answer you linked seems to do the trick. Thanks! Regarding the other alternative: specifying the classpath on the command line, I thought the -jar option for the java command ignores the -cp option, so not sure how one would go about doing that. – freieschaf Apr 10 '20 at 10:21

score -1 · Answer 2 · answered Apr 09 '20 at 18:41

-1

Use this in your pom.xml and rebuild your project.

<dependency>
<groupId>com.google.api.client</groupId>
<artifactId>google-api-client-json</artifactId>
<version>1.1.0-alpha</version>
</dependency>

answered Apr 09 '20 at 18:41

sunil c.j

34
3

Just tried your suggestion but I'm getting the same result at runtime. – freieschaf Apr 09 '20 at 18:46

NoClassDefFoundError as I run a Maven packaged JAR file

2 Answers2