MindTree – Hadoop Interview Questions
Here is the list of Hadoop Interview Questions which are recently asked in MindTree company. These questions are included for both Freshers and Experienced professionals.
1. What is heap error and how can you fix it?
Heap errors can occur when your code inadvertently overwrites control information that the memory management functions use to the control heap usage. The application that you are debugging must have been built with the heap check capability.
2. How many joins does MapReduce have and when will you use each type of join?
There are two types of join operations in MapReduce are: Map Side Join: As the name implies, the join operation is performed in the map phase itself. Therefore, in the map side join, the mapper performs the join and it is the mandatory that the input to each map is partitioned and the sorted according to the keys.
3. What are sinks and sources in Apache Flume when working with Twitter data?
Our Source is the Twitter, from where we are streaming the data and our Sink is HDFS, where we are writing the data. In source configuration, we are passing the Twitter source type as org. apache. flume.
4. How many JVMs run on a DataNode and what is their use?
By default it is set to the +1 which means a new JVM is launched per map/reduce task. On the contrary, if it is set to the -1 then a jvm can be used by unlimited number of tasks. In this case tasks executes serially one after other in order to use the same JVM.
5. If you have configured Java version 8 for Hadoop and Java version 7 for Apache Spark, how will you set the environment variables in the basic configuration file?
The environment variables store data that is used by the operating system and the other programs. For example, the WINDIR environment variable contains the location of the Windows installation directory. Programs can query the value of this variable to determine where the Windows operating system files are located.
6. Differentiate between bash and basic profile.
Basic profile is read and executed when Bash is invoked as an interactive login shell, while . bash is executed for an interactive non-login shell. Basic profile to run commands that should run only once, such as customizing the $PATH environment variable .
TOP MNC's HADOOP INTERVIEW QUESTIONS & ANSWERS
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