In today’s enterprise Java development, you will use plethora of tools to make your life easier and more productive. The open-ended questions described below are not to make the Hire/No Hire decision, but to judge your seniority and experience.
Q. Can you describe some real life scenarios in which tools helped you solve issues?
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Q. How do you perform transaction management in SQL stored procedures?
A. Handled with begin, commit, and rollback ‘tran’ commands in Sybase server.
Q. Why is it important?
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Q. Is there anything wrong with the following class design? If yes, can the design be improved?
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package com.ocp; import javax.management.RuntimeErrorException; import org.apache.commons.lang.StringUtils; public class MathOperation { public int operate(int input1, int input2, String operator){ if(StringUtils.isEmpty(operator)){ throw new IllegalArgumentException("Invalid operator: " + operator); } if(operator.equalsIgnoreCase("+")){ return input1 + input2; } else if(operator.equalsIgnoreCase("*")){ return input1 * input2; } else { throw new RuntimeException("unsupported operator: " + operator); } } } |
JUnit test class.
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package com.ocp; import junit.framework.Assert; import org.junit.Before; import org.junit.Test; public class MathOperationTest { MathOperation operation; @Before public void init(){ operation = new MathOperation(); } @Test public void testAddition() { Assert.assertEquals(8, operation.operate(5, 3, "+")); } @Test public void testMultiplication() { Assert.assertEquals(15, operation.operate(5, 3, "*")); } } |
A. It’s not a good idea to try to anticipate changes in requirements ahead of time, … Read more ›...
Q. Why is it important to set proper timeout values in your applications?
A. Security and performance.
Security reason: it is often necessary to control how long a Web Service client or other valuable clients invoking valuable resources like database connections,
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When you are using Linux/Unix command line frequently, using the history effectively can be a major productivity boost. You can accomplish things with less typing. For example, you will be typing lots of commands like
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ls -ltr cd /tmp/user pwd cd /tmp/usr |
and so on. There are 6 ways to repeat your previous commands quickly without having to type a lot.
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Q1 How will you delete files that are older than 7 days in a remote unix server?
A1 By ssh ing to the remote host server
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ssh user@host123 "find /etc/data/*.csv -mtime +7 -exec rm -f {} \;" >> myapp.log 2>&1 |
Q2 How will you copy files from a remote server to a local server?
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Q1. How will you move files that are older than X (e.g 7) days to their own archive folders to be zipped later on? A1.
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#!/bin/sh -x # DIRPATH=$1 -- path to source files # ARCPATH=$2 -- path to move archived files # WAITTIME=$3 -- days to archive e.g +7 files (older than 7 days) DIRPATH=$1 ARCPATH=$2 WAITTIME=$3 if [ ! -d $ARCPATH ]; then mkdir $ARCPATH fi cd $DIRPATH FILES=`/usr/bin/find . ! -name . -prune -type f -mtime $WAITTIME` for file in $FILES do #for each file find the creating date so that it can be archived under that directory #returns something like 2013Apr26 DATE=` ls -e $file| awk '{print $11"-"$8"-"$9}' | sed 's/-//g'` if [ ! -d $ARCPATH/$DATE ]; then mkdir $ARCPATH/$DATE fi echo "Moving " $file " to " $ARCPATH/$DATE mv $file $ARCPATH/$DATE done; exit 0 |
you run it like
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sh archive.sh /etc/myapp /etc/archive +7 |
The files will be archived under “/etc/archive/{date}” … Read more ›...
sed (stream editor) is one of the powerful workhorse commands in UNIX. Recently I had to use it with “Git” and “Maven” to find text “SNAPSHOT” in all pom.xml files, and manually update them with a realease version like 1.0.2 without the suffix “SNAPSHOT”.
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Many industrial Java applications are developed om a WIN32 platfor, but run on a target platform, which is Unix based. If you are a beginner to Unix, and would like to work on an emulator that runs on a Win32 platform, this post is for you. MobaXterm is a set of Unix commands (GNU/Cygwin) included in a single portable exe file.
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According to Dice’s 2017 Salary Survey (PDF), those tech professionals who specialise in data warehousing, analytics, Big Data, low latency, and machine learning got paid big bucks for the past several years.
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Some design patterns do have subtle differences, and it is important to understand the intent of a pattern. Decorator and chain of responsibility may look similar, but the intent is different. Decorator has a subtle difference with a proxy design pattern. Proxy, Decorator, Adapter, and Bridge are all variations on wrapping a class.
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Q1. Why is a good API design important? A1. The Application Programming Interfaces (i.e. APIs) are fine grained services/libraries used by other applications, systems and libraries. A good API design improves flexibility, stability, and extendability of your application. Now a days, applications are built as reusable components or services. …...
This is not only one of the most popular Java OOP Interview Questions & Answers asked 90% of the time in job interviews, but also a key OOP concept you must know well.
The correct answer depends on the problem you are trying to solve, and the answer you give reveal a lot about your know-hows &
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I have a good news, I got job offer. I like to share with you from my bottom of my heart feeling thankful to you.