flink-quickstart-java Exception in thread "main" java.lang.RuntimeException: No data sinks have been created yet

Question

I have just created new Flink project using maven archetype (i.e. template) (Looking at this article)

mvn archetype:generate                               \
      -DarchetypeGroupId=org.apache.flink              \
      -DarchetypeArtifactId=flink-quickstart-java

1.14.4 is current version. The project can compile. But when running either BatchJob or StreamingJob

public class BatchJob {

    public static void main(String[] args) throws Exception {
        // set up the batch execution environment
        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

The first Exception NoClassDefFoundError: org/apache/flink/streaming/api/environment/StreamExecutionEnvironment can be solved as in java.lang.NoClassDefFoundError: org/apache/flink/streaming/api/scala/StreamExecutionEnvironment

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/flink/streaming/api/environment/StreamExecutionEnvironment
    at com.example.flink.StreamingJob.main(StreamingJob.java:39)
Caused by: java.lang.ClassNotFoundException: org.apache.flink.streaming.api.environment.StreamExecutionEnvironment
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    ... 1 more

But then I get Exception in thread "main" java.lang.RuntimeException: No data sinks have been created yet.

P.S. All links to documentation https://flink.apache.org/docs/latest from these 2 Java classes are 404 Not Found,
so I guess this maven archetype was in fact abandoned and not updated for some time.

         * Have a look at the programming guide for the Java API:
         *
         * https://flink.apache.org/docs/latest/apis/batch/index.html
         *
         * and the examples
         *
         * https://flink.apache.org/docs/latest/apis/batch/examples.html

If you follow these instructions -- nightlies.apache.org/flink/flink-docs-release-1.14/docs/dev/… -- it should work. — David Anderson
– David Anderson, Commented Apr 23, 2022 at 12:14
Thanks for pointing to docs Project Configuration - Maven Quickstart section. And that is exactly problem, and that project, which come with maven flink-quickstart-java archetype use, is in fact not runnable. I went with Fraud Detection with the DataStream API example nightlies.apache.org/flink/flink-docs-release-1.14/docs/… using flink-walkthrough-datastream-java and it just worked. See P.S. in the question now. — Paul Verest
– Paul Verest, Commented Apr 23, 2022 at 15:41

David Anderson · Accepted Answer · 2022-04-25 15:14:51Z

1

The maven quickstart does provide a properly setup skeleton project. However, the supplied applications aren't complete and don't run out of the box because they lack sources and sinks.

If you define a simple pipeline such as

env.fromElements(1, 2, 3).print();

then they will work.

edited Apr 25, 2022 at 15:14

answered Apr 23, 2022 at 17:09

David Anderson

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Paul Verest Over a year ago

This minimal line worked for both ExecutionEnvironment and StreamExecutionEnvironment

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