Github user zentol commented on the issue:
https://github.com/apache/flink/pull/3748
```
[ERROR]
src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraRowSink.java:[20,8]
(imports) UnusedImports: Unused import:
org.apache.flink.configuration.Configuration.
[ERROR]
src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraRowSink.java:[23,8]
(imports) UnusedImports: Unused import:
com.datastax.driver.core.PreparedStatement.
[ERROR]
src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraRowSink.java:[24,8]
(imports) UnusedImports: Unused import: com.datastax.driver.core.ResultSet.
[ERROR]
src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraRowSink.java:[25,8]
(imports) UnusedImports: Unused import:
com.google.common.util.concurrent.ListenableFuture.
```
---
