Why do I get "Exception in thread "main" java.lang.NoClassDefFoundError: org/openqa/selenium/WebDriver"? - maven

Question

I tried some of the advices given on other similar questions here, but failed to overcome the problem.
I am getting this error when trying to execute the jar by:
java -jar AutoHotRouter-1.0.jar
Given the following pom.xml, what am I missing here??
<?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.ttt</groupId>
<artifactId>AutoHotRouter</artifactId>
<version>1.0</version>
<packaging>jar</packaging>
<name>AutoHotRouter</name>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.11.2</version>
</dependency>
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-api</artifactId>
<version>2.53.1</version>
</dependency>
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-chrome-driver</artifactId>
<version>2.53.1</version>
</dependency>
</dependencies>
<build>
<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<plugins>
<!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
<plugin>
<artifactId>maven-site-plugin</artifactId>
<version>3.7.1</version>
</plugin>
<plugin>
<artifactId>maven-project-info-reports-plugin</artifactId>
<version>3.0.0</version>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
First I added:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>prepare-package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>
${project.build.directory}/libs
</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>libs/</classpathPrefix>
<mainClass>com.ttt.App</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
I built the jar using
mvn clean install
then on
java -jar AutoHotRouter.jar
I got:
Exception in thread "main" java.lang.NoClassDefFoundError:
org/openqa/selenium/WebDriver
Then I removed the previous plugins and added firstly maven-assembly-plugin and because it didn't work for me, I replaced it with maven-shade-plugin:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.3.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>com.ttt.App</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<shadedArtifactAttached>true</shadedArtifactAttached>
<transformers>
<transformer implementation=
"org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>com.ttt.App</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
after
mvn clean install
and then
java -jar AutoHotRouter-1.0.jar
I get:
no main manifest attribute
I also tried
mvn clean compile assembly:single
with
maven-assembly-plugin.
Then I got:
Error reading assemblies: No assembly descriptors found.
Thanks!

Answer 1

This is just an assumption since the pom looks good so far. The part that's a bit suspicious is the jar plugin:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.1</version>
<configuration>
...
It looks like you later on try to execute the created jar file with java -jar? In that case all the dependencies you define in the pom will be missing. Either use the dependency-plugin to collect the dependency jar files and use the classpath option when running the jar or use the shade-plugin to create an uber-jar that will contain your classes as well as the dependencies.
Using your pom allowed me to start Chrome, so the dependencies look good. So I think the way you start it causes that exception.
Update: since you use this setup to automate chrome, the shade plugin seems the best way to go. I am able to start chrome with this pom and main class in src/main/java
<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>org.example</groupId>
<artifactId>HotRouter</artifactId>
<version>1.0-SNAPSHOT</version>
<name>HotRouter</name>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-java</artifactId>
<version>3.141.59</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.14.0</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.2.4</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<transformers>
<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>org.example.StartMain</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
Main-Class
package org.example;
import org.openqa.selenium.chrome.ChromeDriver;
public class StartMain {
public static void main(String[] args) {
System.setProperty("webdriver.chrome.driver", "C:/Program Files/Google/Chrome/Application/chrome.exe");
ChromeDriver driver = new ChromeDriver();
}
}
Then mvn package and java -jar ./target/HotRouter-1.0-SNAPSHOT.jar opens chrome. Your config is almost the same (I think only the phase config for the shade plugin is missing)
Its important to have the shade plugin within the <plugins> section of the pom, as it is not part of the default jar life-cycle. The <pluginManagement> section is just there to configure defaults for versions and configuration. See pom reference. So additional plugins will not be automatically enabled if only in that section.