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Java giving NoClassDefFoundError when importing maven package

I have a simple java code, App.java. I am trying to import the apache commons Fraction class from the apache commons math3 library. So, as a sample code, I put this in my App.java:
package myApp;
import org.apache.commons.math3.fraction.Fraction;
public class App
{
public static void main( String[] args )
{
Fraction f = new Fraction(2, 3);
System.out.println( "Hello World!" );
System.out.println( f );
}
}
Using the following POM:
<?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>myApp</groupId>
<artifactId>Proj1</artifactId>
<version>1.0-SNAPSHOT</version>
<name>Proj1</name>
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-math3 -->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-math3</artifactId>
<version>3.6.1</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-jar-plugin</artifactId>
<version>3.0.2</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>
<!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
<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>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.2.4</version>
<configuration>
<!-- put your configurations here -->
</configuration>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
I have tried to put the plugin suggested by utdemir in his answer to a similar question, but in my case, when I run:
mvn package
java -cp target/Proj1-1.0-SNAPSHOT.jar myApp.App
While it apparently compiles properly, I get the following error:
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/math3/fraction/Fraction
at myApp.App.main(App.java:8)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.math3.fraction.Fraction
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:636)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:182)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:519)
... 1 more
What should I do?

Its much easier to run your app using mvn, rathen than by calling java directly. This is because in the later case you need to manually set the classpath to the correct value using the -cp flag. This can lead to errors, like in your case.
Here's how you can run your app using mvn
mvn exec:java -Dexec.mainClass="myApp.App"
More details can be found here

Spark fails with NoClassDefFoundError for org.apache.kafka.common.serialization.StringDeserializer

I am developing a generic Spark application that listens to a Kafka stream using Spark and Java.
I am using kafka_2.11-0.10.2.2, spark-2.3.2-bin-hadoop2.7 - I also tried several other kafka/spark combinations before posting this question.
The code fails at loading StringDeserializer class:
SparkConf sparkConf = new SparkConf().setAppName("JavaDirectKafkaWordCount");
JavaStreamingContext jssc = new JavaStreamingContext(sparkConf, Durations.seconds(2));
Set<String> topicsSet = new HashSet<>();
topicsSet.add(topics);
Map<String, Object> kafkaParams = new HashMap<>();
kafkaParams.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, brokers);
kafkaParams.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
kafkaParams.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
kafkaParams.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
The error I get is:
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/kafka/common/serialization/StringDeserializer
From Why does Spark application fail with "Exception in thread "main" java.lang.NoClassDefFoundError: ...StringDeserializer"? it seems that this could be a scala version mismatch issue, but my pom.xml doesn't have that issue:
<?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>yyy.iot.ckc</groupId>
<artifactId>sparkpoc</artifactId>
<version>1.0-SNAPSHOT</version>
<name>sparkpoc</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<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>
<java.version>1.8</java.version>
<spark.scala.version>2.11</spark.scala.version>
<spark.version>2.3.2</spark.version>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-core_${spark.scala.version}</artifactId>
<version>${spark.version}</version>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-streaming_${spark.scala.version}</artifactId>
<version>${spark.version}</version>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-streaming-kafka-0-10_${spark.scala.version}</artifactId>
<version>${spark.version}</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-jar-plugin</artifactId>
<version>3.0.2</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>
<!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
<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>
The submission script I use is:
./bin/spark-submit \
--class "yyy.iot.ckc.KafkaDataModeler" \
--master local[2] \
../sparkpoc/target/sparkpoc-1.0-SNAPSHOT.jar
Can anyone please point me in the right direction as to where I am going wrong?

Spark runs the program as by running an instance of a JVM. So if the libraries (JARs) are not in the classpath of that JVM we run into this runtime exception. The solution is to package all the dependent JARs along with main JAR. The following build script will work for that.
Also, as mentioned in https://stackoverflow.com/a/54583941/1224075 the scope of the spark-core and spark-streaming libraries need to be declared as provided. This is because some of the libraries are implicitly provided by the Spark JVM.
The build section of the POM which worked for me -
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.2.1</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>

You need to use the Maven Shade Plugin to package the Kafka clients along with your Spark application, then you can submit the shaded Jar, and the Kafka serializers should be found on the classpath.
Also, make sure you set the provided Spark packages
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-core_${spark.scala.version}</artifactId>
<version>${spark.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-streaming_${spark.scala.version}</artifactId>
<version>${spark.version}</version>
<scope>provided</scope>
</dependency>

Maven Deploying Project as Jar - Missing Class definition

I am trying to create a runnable jar from a maven project created in Intellij Idea.
I tried building the Artifact through Intellij, but that did not work out. It could not find the main file.
After that I tried it through maven with:
- mvn compile
- mvn package
This creates a runnable jar which executes, but later when parsing a csv it throws an Exception:
Exception in thread "JavaFX Application Thread"
java.lang.NoClassDefFoundError: org/apache/commons/csv/CSVParser
But it is added in my pom.xml... I downloaded everything even the docs. I can see the org.apache.commons:commons-csv package in the external libraries, but it seems to be missing when creating the jar.
<?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>
<packaging>jar</packaging>
<groupId>sceosa</groupId>
<artifactId>CEO_SA_ReportingLine</artifactId>
<version>1.0-SNAPSHOT</version>
<build>
<finalName>CEOSA</finalName>
<plugins>
<!-- download source code in Eclipse, best practice -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-eclipse-plugin</artifactId>
<version>2.9</version>
<configuration>
<downloadSources>true</downloadSources>
<downloadJavadocs>false</downloadJavadocs>
</configuration>
</plugin>
<!-- Set a compiler level -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<!-- Make this jar executable -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.1.0</version>
<configuration>
<archive>
<manifest>
<mainClass>de.Main</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.hsqldb/hsqldb -->
<!-- https://mvnrepository.com/artifact/org.apache.maven.plugins/maven-compiler-plugin -->
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.7.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.google.guava/guava -->
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>25.1-jre</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-csv</artifactId>
<version>1.3</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
Can anybody see what is wrong with the pom file or intellij?

By default maven does not include dependencies when building jars. The jar will only work if you have the dependency in some other way.
You can use the maven-assembly-plugin to build a jar-with-dependencies.

I have used the maven-shade-plugin and it works great if you want to bundle all your dependencies into one jar. All you need is the plugin and provide the Main class from your project and it should have a main method. It will look something like this:
<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.test.MainClass</mainClass>
                </transformer>
            </transformers>
        </configuration>
        </execution>
    </executions>
</plugin>
And just build your project using mvn clean install and you should find the the jar in your target directory and it will be suffixed with -shaded.jar. Hope this helps

unable to find logger class while running a maven build jar file

I am trying to write a maven integrated Java API. I have included log4j for logging purpose. Which works well when running through eclipse, but when maven package is done and the jar is run it is unable to run from cmd line using java -jar jar_name.jar throwing an error
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Logger
Now the log4j.properties file is placed under src/main/resources folder. And the pom.xml is mentioned. Have tried searching for answers but none worked for me.
Any help available
<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>Weather_Simulator</groupId>
<artifactId>weather_simulator</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>weather_simulator</name>
<url>http://maven.apache.org</url>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>com.test.weather.simulator.MainClass</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<!-- NOTE: We don't need a groupId specification because the group is
org.apache.maven.plugins ...which is assumed by default.
-->
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.1</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-configuration2</artifactId>
<version>2.1.1</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.6.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>

Your <scope> in your pom.xml appears to be wrong. Try this (notice I've changed "test" to "compile").
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.6.1</version>
<scope>compile</scope> <!-- look here -->
</dependency>
The way you currently have your pom.xml configured (with "test"), maven will only provide the log4j jar when doing "mvn test". If you need the jar at both compile time and run time (which is the scenario that appears to be causing problems for you), the scope needs to be "compile".
Note that "compile" is the default scope, so if you leave the <scope> element off, the scope will be "compile".
From the maven docs: "This [compile] is the default scope, used if none is specified. Compile dependencies are available in all classpaths of a project. Furthermore, those dependencies are propagated to dependent projects"
For more info about maven "scopes" look here.

This is a classpath problem, the jar generated by Maven contains only your classes. To fix this you can pack all the dependencies inside your project jar: How can I create an executable JAR with dependencies using Maven?

There are two things you should be aware if you like to create an executable jar which contains all dependent jars you have to use maven-assembly-plugin as you already did but you forgot to bind it to the life cycle...which looks like this:
<project>
[...]
<build>
[...]
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</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>
[...]
</project>
Furthermore having plugins as dependencies is simply wrong..
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.1</version>
</dependency>
This means remove this entry from your pom file.
Defining a dependency with a scope test means it will be available only during the unit tests which means also it will never being packaged into a resulting jar file. This means you have to change the following:
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.6.1</version>
<scope>test</scope>
</dependency>
into the following:
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.6.1</version>
</dependency>
After you have fixed those issues you should be able to build your app via:
mvn clean package
and find the resulting jar file which contains the dependencies in the target directory named like weather_simulator-1.0.0-SNAPSHOT-jar-with-dependencies.jar which you should use to call your app.

Not adding JARs to staging folder on Google Cloud when using Maven

I'm running integration tests on the cloud for the Google Cloud Dataflows that I have written; checking that they read from Pub/Sub and write to BigQuery correctly, but when using Maven (mvn clean install), the staging folder is not populated with the required JARs. The only JAR that appears is a surefirebooter.jar. As a result, I get a NoClassDefFoundError for PipelineOptions (most likely because it is the first class from a dependency that's trying to be referenced) in the Stackdriver logs, and consequently the tests fail. Since they're running on the cloud I am indeed using a DataflowRunner as opposed to a DirectRunner.
When I run the integration tests from my IDE they work fine; the staging folder is populated with all the JARs and all is well. Also, when I run the tests using Maven but with a DirectRunner the tests run successfully, thus my problem only occurs when using Maven and a DataflowRunner. I assume that problem therefore lies with the pom.xml file, which I have given below:
<?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>group</groupId>
<artifactId>artifact</artifactId>
<version>1.0-SNAPSHOT</version>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.5</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<appendAssemblyId>false</appendAssemblyId>
<archive>
<manifest>
<addClasspath>true</addClasspath>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>com.google.cloud.dataflow</groupId>
<artifactId>google-cloud-dataflow-java-sdk-all</artifactId>
<version>2.0.0-beta3</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>5.0.0-M3</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-all</artifactId>
<version>2.0.2-beta</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
Anyone know why this is happening and how I may resolve it?

When staging files, the Dataflow runner will automatically stage the the classes available to the current class loader. I believe that surefire plays some tricks with the classloader to make the tests easier to run.
One option would be to specify filesToStage on the pipeline options, which will override the normal "detect JARs to stage from the class loader". Alternatively, look at how surefire is managing the classpath, and make sure the SDK JARs are available in the classloader the test is running in.