I have the same issue. I am following both the documentation in  https://www.bmc.com/blogs/how-to-write-a-hive-user-defined-function-udf-in-java/ and the link mentioned in previous post: https://www.cloudera.com/documentation/enterprise/5-8-x/topics/cm_mc_hive_udf.html . These are the steps I have taken:   1) The goal is to create a temporary user defined function FNV.java. I have put in dir /src/main/java/com/company/hive/udf/FNV.java the following code: package com.company.hive.udf; import org.apache.hadoop.hive.ql.exec.UDF; import org.apache.hadoop.hive.ql.exec.Description; import org.apache.hadoop.io.Text; import java.math.BigInteger; public final class FNV extends UDF{ <...all tha java code...> } 2)I have added the 2 required JARS for the imports to the CLASSPATH, compiled, build a jar out of this: /src/main/java/com/company/hive/udf/FNV.jar. This is present on the host where the hive metastore and hiveserver2 is running. I check with jar tvf FNV.jar and see that my class src/main/java/com/company/hive/udf/FNV.class is present 3)I put the FNV.jar file on hdfs and did a chown hive:hive and a chmod with full 777 rights 4)I changed the configuration for 'Hive Auxiliary JARs Directory' in Hive to the path of the jar: /src/main/java/com/company/hive/udf/ 5)I redeployed the client config and restarted hive. Here I notice that the 2nd hiveserver (on a different node-not where the JAR is located) has trouble restarted. The host with the hive metastore, hiveserver2 and the jar is up and running. 6) I granted access to the hdfs location and the file on the local host to a role called 'hive_jar'. This is done by logging into beeline !connect jdbc:hive2://node009.cluster.local:10000/default GRANT ALL ON URI 'file:///src/main/java/com/company/hive/udf/FNV.jar' TO ROLE HIVE_JAR; GRANT ALL ON URI 'hdfs:///user/name/FNV.jar' TO ROLE HIVE_JAR; I do notice that SHOW CURRENT ROLES in beeline for the hive user does give the HIVE_JAR role as wanted. 7)I start hive and add the jar using the local hosts's path: add jar /src/main/java/com/company/hive/udf/FNV.jar; I check with list jars that the jar is present 😎 In the same session I try to create the temporary function: create temporary function FNV as 'com.company.hive.udf.FNV'; I keep on getting error : FAILED: Class com.company.hive.udf.FNV not found FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.FunctionTask     Any clue what I am missing?? THanks for feedback! ... View more