title: How do I fix this Kryo exception when using a UDF on hive?
body: <p>I have a hive query that worked in hortonworks 2.6 sandbox, but it doesn't work on sandbox ver. 3.0 because of this exception:</p>
  
  <pre><code>Caused by: org.apache.hive.com.esotericsoftware.kryo.KryoException: Encountered unregistered class ID: 95                                                                                                          
  Serialization trace:                                                                                                                                                                                               
  parentOperators (org.apache.hadoop.hive.ql.exec.vector.reducesink.VectorReduceSinkLongOperator)                                                                                                                    
  childOperators (org.apache.hadoop.hive.ql.exec.vector.VectorFilterOperator)                                                                                                                                        
  childOperators (org.apache.hadoop.hive.ql.exec.TableScanOperator)                                                                                                                                                  
  aliasToWork (org.apache.hadoop.hive.ql.plan.MapWork)                                                                                                                                                               
          at org.apache.hive.com.esotericsoftware.kryo.util.DefaultClassResolver.readClass(DefaultClassResolver.java:137)                                                                                            
          at org.apache.hive.com.esotericsoftware.kryo.Kryo.readClass(Kryo.java:670)                                                                                                                                 
          at org.apache.hadoop.hive.ql.exec.SerializationUtilities$KryoWithHooks.readClass(SerializationUtilities.java:185)  
  </code></pre>
  
  <p>How do I fix it?</p>
  
  <p>I have seen some answers suggesting doing <code>set hive.exec.parallel=false;</code> but it doesn't work, I still get this error.</p>
  
  <p>I checked the versions of libraries that I use and made sure that <code>hadoop version</code> and <code>hive --version</code> match the versions of libraries that I use in my jar.</p>
  
  <p>I also tried this: <a href="https://community.hortonworks.com/content/supportkb/150199/orgapachehivecomesotericsoftwarekryokryoexception-1.html" rel="nofollow noreferrer">https://community.hortonworks.com/content/supportkb/150199/orgapachehivecomesotericsoftwarekryokryoexception-1.html</a> it did not work either.</p>