I cannot reproduce. After adding JAR file to dependencies and adding an import statement on top of the class file everything worked as expected. Maybe try to change scope?

Dependencies:

Class file:

You are using maven but you are running the application from command line so you need to provide all the required jars to your application:

Approach 1: You can provide into your classpath like below:

$ java -jar -cp "list-of-jars" target/my-app.jar -csv test.csv

If you are on Windows the path will be semi colon separated and on Linux it will colon separated. You can use wild cards also like /*.jar to include all the jars(java6+).

Approach 2: You can use one fat/uber/one jar to combine all the jars into on jar run it like you want.

Below is using one-jar:

Using Maven: you need to update the plugins section pom.xml:

<plugin>
        <groupId>org.dstovall</groupId>
        <artifactId>onejar-maven-plugin</artifactId>
        <version>1.4.4</version>
        <executions>
          <execution>
            <goals>
                <goal>one-jar</goal>
            </goals>
          </execution>
        </executions>
    </plugin>

And update pluginRepositories section in pom.xml

<pluginRepository>
        <id>onejar-maven-plugin.googlecode.com</id>
        <url>http://onejar-maven-plugin.googlecode.com/svn/mavenrepo</url>
</pluginRepository>

When you will execute the mvn package you will get yourappname-one-jar.jar and you can run it java -jar yourappname-one-jar.jar

Approach 3: To use the maven shade plugin (as Robert suggested):

Add this into the plugins section of pom.xml:

<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>
              <transformers>
                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                  <mainClass>org.sonatype.haven.HavenCli</mainClass>
                </transformer>
              </transformers>
            </configuration>
          </execution>
        </executions>
      </plugin>

Upon execution on mvn package the uber jar will be generated.

"Install new software" is for adding features to Eclipse itself, not for downloading third-party libraries for your application. For that, you either use a build script (Maven, Gradle, Ivy, ...) for your project, or you download the library code and add it as "External Archive" to the Build Path of your project.