java.lang.ClassNotFoundException: org.apache.pdfbox.multipdf.PDFMergerUtility

Question

I try to combine mutliple PDFs into one using PDFBox. I was following this tutorial from tutorialpoint. But whenever I run it (java -jar pdftool.jar ./pdf-files/*) it throws the following error. Following is the main.java file and the pom.xml for maven.

error

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/pdfbox/multipdf/PDFMergerUtility
        at ch.jocomol.lw.Main.main(Main.java:14)
Caused by: java.lang.ClassNotFoundException: org.apache.pdfbox.multipdf.PDFMergerUtility
        at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
        ... 1 more

pom.xml

<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>ch.jocomol.lw</groupId>
    <artifactId>pdftool</artifactId>
    <version>0.0.1</version>
    <packaging>jar</packaging>
    <dependencies>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>pdfbox</artifactId>
            <version>2.0.20</version>
        </dependency>
        <dependency>
            <groupId>org.bouncycastle</groupId>
            <artifactId>bcprov-jdk15on</artifactId>
            <version>1.66</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.1.0</version>
                <configuration>
                    <finalName>pdftool</finalName>
                    <archive>
                        <manifest>
                            <addClasspath>true</addClasspath>
                            <classpathPrefix>lib/</classpathPrefix>
                            <mainClass>ch.jocomol.lw.Main</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
</project>

import org.apache.pdfbox.multipdf.PDFMergerUtility;

import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;

public class Main {

    public static void main(String[] args) throws IOException {
        List<String> argsList = Arrays.asList(args);
        PDFMergerUtility PDFmerger = new PDFMergerUtility();
        PDFmerger.setDestinationFileName("Unsigned_Joined_Document.pdf");
        for (String pdfFile : argsList){
            PDFmerger.addSource(new File(pdfFile));
            System.out.println("Merging: " + pdfFile);
        }
        PDFmerger.mergeDocuments(null);
    }
}

In other questions it was mentioned that the hard dependencies of PDFBox could be missinng but as you can see, I included the hard dependencies in my pom.xml but it didn't change anything.

Answer 1

Thanks to Lalit Mehra I found out what the problem was. The my Jar didn't include the jar of PDFBox so the class wasn't available. I solved by adding the maven-assembly-plugin to my pom.xml

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <!--suppress MavenModelInspection -->
                <artifactId>maven-assembly-plugin</artifactId>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>single</goal>
                        </goals>
                        <configuration>
                            <descriptorRefs>
                                <descriptorRef>jar-with-dependencies</descriptorRef>
                            </descriptorRefs>
                            <finalName>pdftool</finalName>
                            <appendAssemblyId>false</appendAssemblyId>
                            <archive>
                                <manifest>
                                    <mainClass>
                                        ch.admin.wbf.isceco.lw.Main
                                    </mainClass>
                                </manifest>
                            </archive>
                        </configuration>
                    </execution>
                </executions>
            </plugin>