41.Give a Sqoop command to import all the records from employee table divided into groups of records by the values in the column department_id. $ sqoop import –connect jdbc:mysql://db.foo.com/corp –table …
31.In a sqoop import command you have mentioned to run 8 parallel Mapreduce task but sqoop runs only 4. What can be the reason? The Mapreduce cluster is configured to …
21.How do you clear the data in a staging table before loading it by Sqoop? By specifying the –clear-staging-table option we can clear the staging table before it is loaded. …
11.How can you avoid importing tables one-by-one when importing a large number of tables from a database? Using the command sqoop import-all-tables –connect –usrename –password –exclude-tables table1,table2 .. This will …
1.What is the role of JDBC driver in a Sqoop set up? To connect to different relational databases sqoop needs a connector. Almost every DB vendor makes this connecter available …
41.How to create a session in servlet? You would get HttpSession object by calling the public method getSession() of HttpServletRequest, as below: // Create a session object if it is …
31.Can multiple filters be configured? Yes. 32.Can filtering be done in an ordered way? If so then how to achieve it? Yes. The order of filter-mapping elements in web.xml determines …
21.How to send an authentication error from a servlet? We can use setStatus(statuscode) method of HttpServletResponse to send an authentication error. // Set error code and reason. response.sendError(407, “Need authentication!!!” …
11.For what purpose destroy() method of a servlet is used? This method gives your servlet a chance to close database connections, halt background threads, write cookie lists or hit counts …
1.What are Servlets? Java Servlets are programs that run on a Web or Application server and act as a middle layer between a request coming from a Web browser or …
