Error information
Cause of error
Starting from Flink 1.11, the dependency of flink-streaming-java on flink-clients has been removed and the clients dependency needs to be added manually.
How to Fix
Modify the POM file and add the Flink clients dependency
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-clients_2.12</artifactId>
<version>1.12.2</version>
</dependency>