Cannot have more than one execute() or executeAsync() call in a single environment.

Caused by: org.apache.flink.util.FlinkRuntimeException: Cannot have more than one execute() or executeAsync() call in a single environment. at org.apache.flink.client.program.StreamContextEnvironment.validateAllowedExecution(StreamContextEnvironment.java:139) ~[flink-dist_2.11-1.11.2.jar:1.11.2] at org.apache.flink.client.program.StreamContextEnvironment.executeAsync(StreamContextEnvironment.java:127) ~[flink-dist_2.11-1.11.2.jar:1.11.2]