Apache Flink WordCount Example - Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/flink/api/common/functions/FlatMapFunction

Question

I followed this guide, but I get an Exception if I run WordCount from my IDE

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/usr/lib/jvm/java-8-oracle/bin/java -Didea.launcher.port=7536 -Didea.launcher.bin.path=/home/marc/Programs/idea-IC-162.2032.8/bin -Dfile.encoding=UTF-8 -classpath "/usr/lib/jvm/java-8-oracle/jre/lib/charsets.jar:/usr/lib/jvm/java-8-oracle/jre/lib/deploy.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/cldrdata.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/dnsns.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/jaccess.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/jfxrt.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/localedata.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/nashorn.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/sunec.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/sunjce_provider.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/sunpkcs11.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/zipfs.jar:/usr/lib/jvm/java-8-oracle/jre/lib/javaws.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jce.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jfr.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jfxswt.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jsse.jar:/usr/lib/jvm/java-8-oracle/jre/lib/management-agent.jar:/usr/lib/jvm/java-8-oracle/jre/lib/plugin.jar:/usr/lib/jvm/java-8-oracle/jre/lib/resources.jar:/usr/lib/jvm/java-8-oracle/jre/lib/rt.jar:/home/marc/apache flink/flink.gelly/target/classes:/home/marc/Programs/idea-IC-162.2032.8/lib/idea_rt.jar" com.intellij.rt.execution.application.AppMain haw.bachelor.flink.gelly.WordCount
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/flink/api/common/functions/FlatMapFunction
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:123)
Caused by: java.lang.ClassNotFoundException: org.apache.flink.api.common.functions.FlatMapFunction
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 3 more

my environment:

• Ubuntu 14.04 LTS
• Oracle Java 8
• Maven 3.0.5
• intellij community edition

Answer 1

here is what i changed setting and the error was gone

Answer 2

In Intellij IDEA (2020.3), the UI is a little different.

Steps:

1. Activate Run-Configuration dropdown
2. click Edit Configurations...
3. click Modify Options
4. select include dependencies with "Provided" scope
5. Click "done"

Flink sources should now be included, which should resolve the error encountered - it did for me!