title: Kafka streams GlobalKTable throws Deserialization exception on Tombstone - null value- records
body: <p>I have a Spring cloud stream based Kafka Streams application where I'm binding a Global KTable to a Compact topic. When I push a Tombstone record to the topic (Non-empty key with null value) - my Kafka streams application fails with Deserialization exception. The failure is because my deserializer does not handle null records.</p>
  <p>From the documentation, I thought GlobalKTable will not even &quot;see&quot; null-value records. Is it not the case? Do I need to handle null records in the deserializer?</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
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  <pre class="snippet-code-html lang-html prettyprint-override"><code>org.apache.kafka.common.errors.SerializationException: Unable to deserialize
  Caused by: java.lang.IllegalArgumentException: argument "src" is null
      at com.fasterxml.jackson.databind.ObjectMapper._assertNotNull(ObjectMapper.java:4693)
      at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3511)
      at common.domain.serdes.MySerde$MyDeserializer.deserialize(MySerde.java:47)
      at common.domain.serdes.MySerde$MyDeserializer.deserialize(MySerde.java:39)
      at org.apache.kafka.streams.processor.internals.SourceNode.deserializeValue(SourceNode.java:63)
      at org.apache.kafka.streams.processor.internals.RecordDeserializer.deserialize(RecordDeserializer.java:66)
      at org.apache.kafka.streams.processor.internals.GlobalStateUpdateTask.update(GlobalStateUpdateTask.java:91)
      at org.apache.kafka.streams.processor.internals.GlobalStreamThread$StateConsumer.pollAndUpdate(GlobalStreamThread.java:240)
      at org.apache.kafka.streams.processor.internals.GlobalStreamThread.run(GlobalStreamThread.java:289)</code></pre>
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  </p>