java.lang.ClassNotFoundException：Maven可运行jar的com.mysql.jdbc.Driver

Question

I'm trying to create .jar file in my server(CentOS) using Maven. It is successfully compiling and generates the .jar file. But when I execute it, it shows the following error. This questions may look like "previously asked" but, I tried all the suggestions from here. What I believe is in my POM.xml have some issue, but I'm not able to find. If someone can verify the POM.xml it would be helpful.

Command:

$ java -jar target/ListDescCrawler-1.1-SNAPSHOT.jar

Error:

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

My 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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>edu.uci.ics.crawler4j</groupId>
  <artifactId>ListDescCrawler</artifactId>
  <packaging>jar</packaging>
  <version>1.1-SNAPSHOT</version>
  <name>SanListDescCrawlerHandu</name>
  <url>http://maven.apache.org</url>
  <build>
      <pluginManagement>
        <plugins>
          <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.3</version>
            <configuration>
              <source>1.7</source>
              <target>1.7</target>            
            </configuration>
          </plugin>
          <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <configuration>
                    <archive>
                        <manifest>
                            <addClasspath>true</addClasspath>
                            <mainClass>edu.uci.ics.crawler4j.example.MainController</mainClass>                         
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
      </pluginManagement>
  </build>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.james</groupId>
        <artifactId>apache-mime4j-core</artifactId>
        <version>0.7</version>
    </dependency>
    <dependency>
        <groupId>org.apache.james</groupId>
        <artifactId>apache-mime4j-dom</artifactId>
        <version>0.7</version>
    </dependency>
    <dependency>
        <groupId>asm</groupId>
        <artifactId>asm</artifactId>
        <version>3.1</version>
    </dependency>
    <dependency>
        <groupId>de.l3s.boilerpipe</groupId>
        <artifactId>boilerpipe</artifactId>
        <version>1.1.0</version>
    </dependency>
    <dependency>
        <groupId>commons-codec</groupId>
        <artifactId>commons-codec</artifactId>
        <version>1.6</version>
    </dependency>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-compress</artifactId>
        <version>1.3</version>
    </dependency>
    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.1.3</version>
    </dependency>
    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>fluent-hc</artifactId>
        <version>4.3.6</version>
    </dependency>
    <dependency>
        <groupId>org.apache.geronimo.specs</groupId>
        <artifactId>geronimo-stax-api_1.0_spec</artifactId>
        <version>1.0.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
        <version>4.3.6</version>
    </dependency>   
    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpcore</artifactId>
        <version>4.3.3</version>
    </dependency>
    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpmime</artifactId>
        <version>4.3.6</version>
    </dependency>
    <dependency>
        <groupId>com.sleepycat</groupId>
        <artifactId>je</artifactId>
        <version>4.0.92</version>
    </dependency>
    <dependency>
        <groupId>org.jsoup</groupId>
        <artifactId>jsoup</artifactId>
        <version>1.8.1</version>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>
    <dependency>
        <groupId>com.drewnoakes</groupId>
        <artifactId>metadata-extractor</artifactId>
        <version>2.4.0-beta-1</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.34</version>
    </dependency>
    <dependency>
        <groupId>org.ccil.cowan.tagsoup</groupId>
        <artifactId>tagsoup</artifactId>
        <version>1.2.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.tika</groupId>
        <artifactId>tika-app</artifactId>
        <version>1.6</version>
    </dependency>
  </dependencies>
</project>

The MANIFEST.MF file in the generated .jar file:

Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Created-By: Apache Maven
Built-By: root
Build-Jdk: 1.7.0_91
Main-Class: edu.uci.ics.crawler4j.example.MainController
Class-Path: apache-mime4j-core-0.7.jar apache-mime4j-dom-0.7.jar asm-3
 .1.jar boilerpipe-1.1.0.jar commons-codec-1.6.jar commons-compress-1.
 3.jar commons-logging-1.1.3.jar fluent-hc-4.3.6.jar geronimo-stax-api
 _1.0_spec-1.0.1.jar httpclient-4.3.6.jar httpcore-4.3.3.jar httpmime-
 4.3.6.jar je-4.0.92.jar jsoup-1.8.1.jar log4j-1.2.17.jar metadata-ext
 ractor-2.4.0-beta-1.jar tagsoup-1.2.1.jar tika-app-1.6.jar tika-parse
 rs-1.6.jar tika-core-1.6.jar vorbis-java-tika-0.6.jar netcdf-4.2.20.j
 ar unidataCommon-4.2.20.jar jcip-annotations-1.0.jar commons-httpclie
 nt-3.1.jar jmatio-1.0.jar xz-1.5.jar pdfbox-1.8.6.jar fontbox-1.8.6.j
 ar jempbox-1.8.6.jar bcmail-jdk15-1.45.jar bcprov-jdk15-1.45.jar poi-
 3.11-beta2.jar poi-scratchpad-3.11-beta2.jar poi-ooxml-3.11-beta2.jar
  poi-ooxml-schemas-3.11-beta2.jar xmlbeans-2.6.0.jar asm-debug-all-4.
 1.jar isoparser-1.0.2.jar aspectjrt-1.8.0.jar rome-1.0.jar jdom-1.0.j
 ar vorbis-java-core-0.6.jar juniversalchardet-1.0.3.jar jhighlight-1.
 0.jar java-libpst-0.8.1.jar tika-serialization-1.6.jar tika-xmp-1.6.j
 ar xmpcore-5.1.2.jar slf4j-log4j12-1.5.6.jar slf4j-api-1.5.6.jar gson
 -1.7.1.jar

Commands executed:

 mvn clean compile
 mvn clean package
 java -jar target/ListDescCrawler-1.1-SNAPSHOT.jar

There are many library files are added to the project including mysql-connector-java-5.1.34.jar. But still the error is showing. I checked in SOF for a solution and tried many suggestions from here, but nothing fixed my issue.

I checked MANIFEST.MF in the generated .jar file and it looks fine.

Other points to note is, its working fine from Eclipse(without Maven)

is there any mistake in my POM.xml?

The suggestions I tried:

1. dependency/scope I tried all the possible values

2. Copied mysql-connector-java-5.1.34.jar in the lib folder and changed the POM.xml accordingly

and may other suggestions but nothing helped.

At last the things started to work with the following 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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>edu.uci.ics.crawler4j</groupId>
    <artifactId>ListDescCrawler</artifactId>
    <packaging>jar</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>SanListDescCrawlerHandu</name>
    <url>http://maven.apache.org</url>

    <properties>
        <jdk.version>1.7</jdk.version>      
        <junit.version>4.11</junit.version>
        <apache-mime4j-core.version>0.7</apache-mime4j-core.version>
        <apache-mime4j-dom.version>0.7</apache-mime4j-dom.version>
        <asm.version>3.1</asm.version>
        <boilerpipe.version>1.1.0</boilerpipe.version>
        <commons-codec.version>1.6</commons-codec.version>
        <commons-compress.version>1.3</commons-compress.version>
        <commons-logging.version>1.1.3</commons-logging.version>
        <fluent-hc.version>4.3.6</fluent-hc.version>
        <geronimo-stax-api_1.0_spec.version>1.0.1</geronimo-stax-api_1.0_spec.version>
        <httpclient.version>4.3.6</httpclient.version>
        <httpcore.version>4.3.3</httpcore.version>
        <httpmime.version>4.3.6</httpmime.version>
        <je.version>4.0.92</je.version>
        <jsoup.version>1.8.1</jsoup.version>
        <log4j.version>1.2.17</log4j.version>
        <metadata-extractor.version>2.4.0-beta-1</metadata-extractor.version>
        <mysql-connector-java.version>5.1.34</mysql-connector-java.version>
        <tagsoup.version>1.2.1</tagsoup.version>
        <tika-app.version>1.6</tika-app.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.james</groupId>
            <artifactId>apache-mime4j-core</artifactId>
            <version>${apache-mime4j-core.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.james</groupId>
            <artifactId>apache-mime4j-dom</artifactId>
            <version>${apache-mime4j-dom.version}</version>
        </dependency>
        <dependency>
            <groupId>asm</groupId>
            <artifactId>asm</artifactId>
            <version>${asm.version}</version>
        </dependency>
        <dependency>
            <groupId>de.l3s.boilerpipe</groupId>
            <artifactId>boilerpipe</artifactId>
            <version>${boilerpipe.version}</version>
        </dependency>
        <dependency>
            <groupId>commons-codec</groupId>
            <artifactId>commons-codec</artifactId>
            <version>${commons-codec.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-compress</artifactId>
            <version>${commons-compress.version}</version>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>${commons-logging.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>fluent-hc</artifactId>
            <version>${fluent-hc.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.geronimo.specs</groupId>
            <artifactId>geronimo-stax-api_1.0_spec</artifactId>
            <version>${geronimo-stax-api_1.0_spec.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>${httpclient.version}</version>
        </dependency>   
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>${httpcore.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
            <version>${httpmime.version}</version>
        </dependency>
        <dependency>
            <groupId>com.sleepycat</groupId>
            <artifactId>je</artifactId>
            <version>${je.version}</version>
        </dependency>
        <dependency>
            <groupId>org.jsoup</groupId>
            <artifactId>jsoup</artifactId>
            <version>${jsoup.version}</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>com.drewnoakes</groupId>
            <artifactId>metadata-extractor</artifactId>
            <version>${metadata-extractor.version}</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql-connector-java.version}</version>
        </dependency>
        <dependency>
            <groupId>org.ccil.cowan.tagsoup</groupId>
            <artifactId>tagsoup</artifactId>
            <version>${tagsoup.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.tika</groupId>
            <artifactId>tika-app</artifactId>
            <version>${tika-app.version}</version>
        </dependency>
    </dependencies>

    <build>
        <finalName>ListDescCrawler</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>${jdk.version}</source>
                    <target>${jdk.version}</target>
                </configuration>
            </plugin>

            <!-- Maven Assembly Plugin -->
            <plugin>
              <artifactId>maven-assembly-plugin</artifactId>
              <configuration>
                <descriptorRefs>
                  <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
                <archive>
                  <manifest>
                    <mainClass>edu.uci.ics.crawler4j.example.MainController</mainClass>
                  </manifest>
                </archive>
              </configuration>
              <executions>
                <execution>
                  <phase>package</phase>
                  <goals>
                    <goal>single</goal>
                  </goals>
                </execution>
              </executions>
            </plugin>

        </plugins>
    </build>

</project>

Answer 1

Eventhough your class path in MANIFEST.MF contains jar that you are dependent it does not mean that they actually on your class path when you run your project. You have two option here either put all the dependent jar in the same directory of your runnable jar, or create a shaded jar.

A shaded (fat) jar contains all of your dependencies. You can create shaded jar using maven. Here is an example.

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>2.4.1</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                    <configuration>
                        <finalName>${project.build.finalName}-with-dependencies</finalName>
                        <transformers>
                            <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                <mainClass> edu.uci.ics.crawler4j.example.MainController </mainClass>
                            </transformer>
                        </transformers>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>