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329 hadoop developer interview questions shared by candidates

1)what is difference between singleton object and companion object? 2)why is scala functional as well as object oriented? 3) any 5 topics for scala functional on which candidate would like to be interviewed? 4)what is case class in scala? syntax of case class. 5)A table has employee details with department. want to find out top 3 salaried employee from each department? 6) what is rack awareness, edge node, speculative execution.? 7.)if a table is getting incremented everyday how to make update in HDFS? Is update possible in HDFS?(HINT: using HBASE) 8.) how to save dataframe as a table in HDFS? syntax for the same 9.)what is multi-threading in java? difference between final and finally 8.)how many types of joins I have worked with 10.)Difference between groupByKey and reduceByKey? what is the harm even if shuffling is more in case groupByKey? 10.)optimization techniques used in HIVE 11.)I am reading a CSV file using spark. what is schema of the file is not known or file columns is not fixed? 12.)difference between executor memory and driver memory? 13.) on which mode u have worked(yarn,standalone cluster,how to decide number of executors) 14.)optimization in spark 15.)why is RDD resilient? have you heard of DAG lineage 16.)question on number of mappers and reducers? why is select * from table query faster than select count(*) from table in hive? 17.) how to set map side join 18.)difference between data frame and dataset . 19)how is a file processed in map reduce? 20.) while executing a bash script how is parameter passed?
avatar

Hadoop Developer

Interviewed at Tata Consultancy Services

3.5★
Jul 24, 2018

1)what is difference between singleton object and companion object? 2)why is scala functional as well as object oriented? 3) any 5 topics for scala functional on which candidate would like to be interviewed? 4)what is case class in scala? syntax of case class. 5)A table has employee details with department. want to find out top 3 salaried employee from each department? 6) what is rack awareness, edge node, speculative execution.? 7.)if a table is getting incremented everyday how to make update in HDFS? Is update possible in HDFS?(HINT: using HBASE) 8.) how to save dataframe as a table in HDFS? syntax for the same 9.)what is multi-threading in java? difference between final and finally 8.)how many types of joins I have worked with 10.)Difference between groupByKey and reduceByKey? what is the harm even if shuffling is more in case groupByKey? 10.)optimization techniques used in HIVE 11.)I am reading a CSV file using spark. what is schema of the file is not known or file columns is not fixed? 12.)difference between executor memory and driver memory? 13.) on which mode u have worked(yarn,standalone cluster,how to decide number of executors) 14.)optimization in spark 15.)why is RDD resilient? have you heard of DAG lineage 16.)question on number of mappers and reducers? why is select * from table query faster than select count(*) from table in hive? 17.) how to set map side join 18.)difference between data frame and dataset . 19)how is a file processed in map reduce? 20.) while executing a bash script how is parameter passed?

It covered almost all topics from mapreduce,hive and core java coz i had wrking experience on these technologies only simple qn like map reduce phase,why sorting/suffling, one simple map reduce program with syntax,join querries etc
avatar

Hadoop Developer

Interviewed at Infosys

3.6★
Aug 8, 2017

It covered almost all topics from mapreduce,hive and core java coz i had wrking experience on these technologies only simple qn like map reduce phase,why sorting/suffling, one simple map reduce program with syntax,join querries etc

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