     SystemProcessingTimeServiceTest.testImmediateShutdown is instable
</li>
<li>[<a href='https://issues.apache.org/jira/browse/FLINK-19777'>FLINK-19777</a>] -         Fix NullPointException for WindowOperator.close()
</li>
<li>[<a href='https://issues.apache.org/jira/browse/FLINK-19790'>FLINK-19790</a>] -         Writing MAP&lt;STRING, STRING&gt; to Kafka with JSON format produces incorrect data.
</li>
<li>[<a href='https://issues.apache.org/jira/browse/FLINK-19806'>FLINK-19806</a>] -         Job may try 