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Cracking an interview for a position using Java can be quite challenging—even though you’re applying for a standard software development job; the SATs appear simple given the variety of questions you might encounter. The purpose of this article is to enlighten you about the kinds of Java interview questions and answers, regardless of their nature. If you have Java on your CV, you could be questioned about everything—from the very first release to the most recent. In essence, how to stay abreast with everything? Let’s find out!Java Interview Questions and Answers for Freshers
These questions cover critical basic Java principles that will greatly aid your preparation. Hence, the following are the top five Java interview questions and answers for new hires.1. What are the Main Distinctions between C++ and Java?
C++ and Java are both object-oriented programming languages with some distinctions. The interviewer may inquire about the distinction between the two and add it among the top Java interview questions for freshers to assess their fundamental understanding.
C++ is platform-dependent.
Java is platform-independent.
It creates structured programs without the need for classes or objects.
With the exception of basic variables, Java is a pure object-oriented language.
Pointers are fully supported in C++.
There is no concept of pointers in Java.
C++ allows for multiple inheritances.
Java does not allow for multiple inheritances.2. What is Thread Priority? 3. Which is Preferred: The Synchronized Method or the Synchronized Block?
The synchronized block is favored because it does not lock the object, whereas synchronized methods do. In fact, if there are several synchronization blocks in the class, even if they are unrelated, it will stop the execution and place them in a wait state to obtain the lock on the object.4. How to Get the Database Server Details in the Java Program?
We may access the database server details by using the DatabaseMetaData object. When the database connection is properly established, we can retrieve the metadata object by invoking the getMetaData() function. There are also other methods in DatabaseMetaData that may be used to determine the product name, version, and configuration parameters.
DatabaseMetaData metadata = con.getMetaData();5. What is a Java Object?
In Java, an object is a data structure that represents a physical entity. An object in Java might be a tangible entity like a vehicle or an abstract idea like a mathematical formula. In addition, each object has its own set of information and behavior. Moreover, the object’s data is the information it holds, but its behavior is its capacity to do certain activities.
ALSO READ: How to Become a Game Developer and Create Great Gaming ExperiencesJava Interview Questions for Experienced Candidates 6. Can the Keywords “This” and “Super” be Used Together?
No, the terms “this” and “super” should not be used in the initial sentence of the class constructor.7. What is Java Session Management?
A session is defined as the dynamic state of random communication between the client and server. The virtual communication channel includes a string of replies and requests from both sides. The most common method of implementing session management is to create a session ID in both the client and server’s communicative discourse.8. What is JCA in Java?
Java Cryptography Architectural (JCA) provides a framework for decryption and encryption, as well as architecture and application programming interfaces. Additionally. Java Cryptography Architecture is used by developers to integrate the application with security applications. In fact, the Java Cryptography Architecture facilitates the implementation of third-party security rules and regulations. To accomplish security, Java Cryptography Architecture uses hash tables, encryption message digests, etc.9. What is the Distinction between chúng tôi chúng tôi and System.in?
System.out and chúng tôi are the monitor’s default representations and may thus be used to deliver data or results to the monitor. chúng tôi is used to output standard messages and results. Error messages are shown using System.eerr. Moreover, chúng tôi provides an InputStream object which represents a conventional input device, such as a keyboard, by default.10. Is it Possible to Overload the Main Method?
Yes, we may overload the main method as many times as we like. Nonetheless, the JVM prefers to use its designated calling mechanism to invoke the main function.
ALSO READ: What is Full Stack Development? The Ultimate 2023 GuideTips for Java Interview Questions and Answers
Here are a few tips for Java interview questions and answers:
Have a realistic resume
Know the fundamentals of computer science
Expect to be asked to write code on a whiteboard or on paper
Listen carefully to the questions
Be thorough with simple and complex Java principles and concepts
Learning more about the Java programming language is now easier than ever: In fact, Emeritus offers a multitude of online coding courses that could help you ace interviews and bag your dream job.
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Introduction to Docker Interview Questions and Answers
Web development, programming languages, Software testing & others
Now, if you are looking for a job that is related to Docker, then you need to prepare for the 2023 Docker Interview Questions. It is true that every interview is different as per the different job profiles. Here, we have prepared the important Docker Interview Questions and Answers, which will help you get success in your interview.
Below are the 10 important 2023 Docker interview questions and answers that are frequently asked in an interview. These questions are divided into two parts are as follows:Part 1 – Docker Interview Questions (Basic)
This first part covers basic Interview Questions and Answers.Q1. What is Docker?
A Docker is defined as the platform for containerizing the applications to isolate them from each other in order to ensure high availability and more efficiency irrespective of the environments such as Development, Testing or Production. All the application related dependencies such as libraries, jar files, server related configurations, infrastructure-related elements will be packaged and formed as container called containerized application which does not need any dependency and works independently. It ensures the application to be run irrespective of external factors. Containers in Docker have support from Docker Engine and Host Operating System to support all the operational or infrastructural-related dependencies.Q2. What are the components of Docker Architecture and explain?
This is the common Docker Interview Questions asked in an interview. The Docker works on client-server architecture. The Docker client establishes communication with the Docker Daemon. The Docker client and daemon can run on the same system. A Docket client can also be connected to a remote Docker daemon. The different types of Docker components in a Docker architecture are–
Docker Client: This performs Docker build pull and run operations to establish communication with the Docker Host. The Docker command uses Docker API to call the queries to be run.
Docker Host: This component contains Docker Daemon, Containers and its images. The images will be the kind of metadata for the applications which are containerized in the containers. The Docker Daemon establishes a connection with Registry.
Registry: This component will be storing the Docker images. The public registries are Docker Hub and Docker Cloud, which can be s used by anyone.Q3. What is Docker Container? Q4. What are Docker Image and Docker Hub?
The Docker Image is a set of files and a combination of parameters that will allow creating the instances to run in separate containers as an isolated process. The Docker hub is a kind of repository to the images where these images can be stored, and this access is public. The Docker run command can be used to create the instance called a container, which can be run using the Docker image. Docker hub is the largest public repository of the image containers, which is being maintained by the community of developers and individual contributors.Q5. What are the different functionalities and applications of using Docker?
The different functionalities and applications of using and implementing Docker are as below:
It simplifies the configuration and provides ease at infrastructure level configuration.
It manages the code pipeline easily, which provides a consistent environment and stability in the application.
It enables the isolation of the application.
It improves the productivity of the developer by allowing the developer to solely concentrate on business logic.
It enables a lot of debugging capabilities that provide extremely useful functionalities to implement.
It enables rapid deployment in the form of virtualization at the operating system level.
It reduces the utilization of multiple servers in the form of containerization.Part 2 – Docker Interview Questions (Advanced) Q6. What is a Docker Registry? Q7. What is the lifecycle of Docker Container?
This is the most popular Docker Interview Questions asked in an interview. The life cycle of the Docker container is as below:
Create a container.
Run the Docker container.
Pause the Container.
Unpause the Container.
Start the Container.
Stop the Container.
Restart the Container.
Kill the Container.
Destroy the Container.Q8. What are Docker Objects?
The Docker Objects are Docker Images, Services, and Docker Containers. A Docker Image is a read-only template with the configuration or runtime instructions for the Docker container. The Services allow scaling the containers across the different Docker Daemons. These all together work as Swarm.Q9. What are Docker Namespaces?
The Namespaces in Docker is a technology that provides isolated workspaces called the Container. Namespaces provide a layer of isolation for the Docker containers.Q10. What are the important Docker commands?
dockerd To launch Docker daemon.
build To build an image file for docker.
create To create a new container.
kill To kill a container.
commit To create a new image from container changes.Recommended Articles
This has been a guide to the list of Docker Interview Questions and Answers so that the candidate can crackdown on these Interview Questions easily. Here in this post, we have studied top Docker Interview Questions, which are often asked in interviews. You may also look at the following articles to learn more –
Here are Hadoop MapReduce interview questions and answers for fresher as well experienced candidates to get their dream job.Hadoop MapReduce Interview Questions 1) What is Hadoop Map Reduce?
For processing large data sets in parallel across a Hadoop cluster, Hadoop MapReduce framework is used. Data analysis uses a two-step map and reduce process.2) How Hadoop MapReduce works?
In MapReduce, during the map phase, it counts the words in each document, while in the reduce phase it aggregates the data as per the document spanning the entire collection. During the map phase, the input data is divided into splits for analysis by map tasks running in parallel across Hadoop framework.
👉 Free PDF Download: Hadoop & MapReduce Interview Questions & Answers3) Explain what is shuffling in MapReduce?
The process by which the system performs the sort and transfers the map outputs to the reducer as inputs is known as the shuffle4) Explain what is distributed Cache in MapReduce Framework?
Distributed Cache is an important feature provided by the MapReduce framework. When you want to share some files across all nodes in Hadoop Cluster, Distributed Cache is used. The files could be an executable jar files or simple properties file.5) Explain what is NameNode in Hadoop?
NameNode in Hadoop is the node, where Hadoop stores all the file location information in HDFS (Hadoop Distributed File System). In other words, NameNode is the centerpiece of an HDFS file system. It keeps the record of all the files in the file system and tracks the file data across the cluster or multiple machines
6) Explain what is JobTracker in Hadoop? What are the actions followed by Hadoop?
In Hadoop for submitting and tracking MapReduce jobs, JobTracker is used. Job tracker run on its own JVM process
Job Tracker performs following actions in Hadoop
Client application submit jobs to the job tracker
JobTracker communicates to the Name mode to determine data location
Near the data or with available slots JobTracker locates TaskTracker nodes
On chosen TaskTracker Nodes, it submits the work
When a task fails, Job tracker notifies and decides what to do then.
The TaskTracker nodes are monitored by JobTracker7) Explain what is heartbeat in HDFS?
Heartbeat is referred to a signal used between a data node and Name node, and between task tracker and job tracker, if the Name node or job tracker does not respond to the signal, then it is considered there is some issues with data node or task tracker8) Explain what combiners are and when you should use a combiner in a MapReduce Job?
To increase the efficiency of MapReduce Program, Combiners are used. The amount of data can be reduced with the help of combiner’s that need to be transferred across to the reducers. If the operation performed is commutative and associative you can use your reducer code as a combiner. The execution of combiner is not guaranteed in Hadoop9) What happens when a data node fails?
When a data node fails
Jobtracker and namenode detect the failure
On the failed node all tasks are re-scheduled
Namenode replicates the user’s data to another node10) Explain what is Speculative Execution?
In Hadoop during Speculative Execution, a certain number of duplicate tasks are launched. On a different slave node, multiple copies of the same map or reduce task can be executed using Speculative Execution. In simple words, if a particular drive is taking a long time to complete a task, Hadoop will create a duplicate task on another disk. A disk that finishes the task first is retained and disks that do not finish first are killed.11) Explain what are the basic parameters of a Mapper?
The basic parameters of a Mapper are
LongWritable and Text
Text and IntWritable12) Explain what is the function of MapReduce partitioner?
The function of MapReduce partitioner is to make sure that all the value of a single key goes to the same reducer, eventually which helps even distribution of the map output over the reducers13) Explain what is a difference between an Input Split and HDFS Block?
The logical division of data is known as Split while a physical division of data is known as HDFS Block14) Explain what happens in text format?
In text input format, each line in the text file is a record. Value is the content of the line while Key is the byte offset of the line. For instance, Key: longWritable, Value: text15) Mention what are the main configuration parameters that user need to specify to run MapReduce Job?
The user of the MapReduce framework needs to specify
Job’s input locations in the distributed file system
Job’s output location in the distributed file system
Class containing the map function
Class containing the reduce function
JAR file containing the mapper, reducer and driver classes16) Explain what is WebDAV in Hadoop?
To support editing and updating files WebDAV is a set of extensions to HTTP. On most operating system WebDAV shares can be mounted as filesystems, so it is possible to access HDFS as a standard filesystem by exposing HDFS over WebDAV.17) Explain what is Sqoop in Hadoop?
To transfer the data between Relational database management (RDBMS) and Hadoop HDFS a tool is used known as Sqoop. Using Sqoop data can be transferred from RDMS like MySQL or Oracle into HDFS as well as exporting data from HDFS file to RDBMS18) Explain how JobTracker schedules a task?
The task tracker sends out heartbeat messages to Jobtracker usually every few minutes to make sure that JobTracker is active and functioning. The message also informs JobTracker about the number of available slots, so the JobTracker can stay up to date with wherein the cluster work can be delegated19) Explain what is Sequencefileinputformat?
Sequencefileinputformat is used for reading files in sequence. It is a specific compressed binary file format which is optimized for passing data between the output of one MapReduce job to the input of some other MapReduce job.20) Explain what does the conf.setMapper Class do?
Conf.setMapperclass sets the mapper class and all the stuff related to map job such as reading data and generating a key-value pair out of the mapper21) Explain what is Hadoop?
It is an open-source software framework for storing data and running applications on clusters of commodity hardware. It provides enormous processing power and massive storage for any type of data.22) Mention what is the difference between an RDBMS and Hadoop?
RDBMS is a relational database management system Hadoop is a node based flat structure
It used for OLTP processing whereas Hadoop It is currently used for analytical and for BIG DATA processing
In RDBMS, the database cluster uses the same data files stored in a shared storage In Hadoop, the storage data can be stored independently in each processing node.
You need to preprocess data before storing it you don’t need to preprocess data before storing it23) Mention Hadoop core components?
Hadoop core components include,
MapReduce24) What is NameNode in Hadoop?
NameNode in Hadoop is where Hadoop stores all the file location information in HDFS. It is the master node on which job tracker runs and consists of metadata.25) Mention what are the data components used by Hadoop?
Data components used by Hadoop are26) Mention what is the data storage component used by Hadoop?
The data storage component used by Hadoop is HBase.27) Mention what are the most common input formats defined in Hadoop?
The most common input formats defined in Hadoop are;
SequenceFileInputFormat28) In Hadoop what is InputSplit?
It splits input files into chunks and assigns each split to a mapper for processing.29) For a Hadoop job, how will you write a custom partitioner?
You write a custom partitioner for a Hadoop job, you follow the following path
Create a new class that extends Partitioner Class
Override method getPartition
In the wrapper that runs the MapReduce
Add the custom partitioner to the job by using method set Partitioner Class or – add the custom partitioner to the job as a config file30) For a job in Hadoop, is it possible to change the number of mappers to be created?
No, it is not possible to change the number of mappers to be created. The number of mappers is determined by the number of input splits.31) Explain what is a sequence file in Hadoop?
To store binary key/value pairs, sequence file is used. Unlike regular compressed file, sequence file support splitting even when the data inside the file is compressed.32) When Namenode is down what happens to job tracker?
Namenode is the single point of failure in HDFS so when Namenode is down your cluster will set off.33) Explain how indexing in HDFS is done?
Hadoop has a unique way of indexing. Once the data is stored as per the block size, the HDFS will keep on storing the last part of the data which say where the next part of the data will be.34) Explain is it possible to search for files using wildcards?
Yes, it is possible to search for files using wildcards.35) List out Hadoop’s three configuration files?
The three configuration files are
hdfs-site.xml36) Explain how can you check whether Namenode is working beside using the jps command?
Besides using the jps command, to check whether Namenode are working you can also use
/etc/init.d/hadoop-0.20-namenode status.37) Explain what is “map” and what is “reducer” in Hadoop?
In Hadoop, a reducer collects the output generated by the mapper, processes it, and creates a final output of its own.38) In Hadoop, which file controls reporting in Hadoop?
In Hadoop, the hadoop-metrics.properties file controls reporting.39) For using Hadoop list the network requirements?
For using Hadoop the list of network requirements are:
Password-less SSH connection
Secure Shell (SSH) for launching server processes40) Mention what is rack awareness?
Rack awareness is the way in which the namenode determines on how to place blocks based on the rack definitions.41) Explain what is a Task Tracker in Hadoop?
A Task Tracker in Hadoop is a slave node daemon in the cluster that accepts tasks from a JobTracker. It also sends out the heartbeat messages to the JobTracker, every few minutes, to confirm that the JobTracker is still alive.42) Mention what daemons run on a master node and slave nodes?
Daemons run on Master node is “NameNode”
Daemons run on each Slave nodes are “Task Tracker” and “Data”43) Explain how can you debug Hadoop code?
The popular methods for debugging Hadoop code are:
By using web interface provided by Hadoop framework
By using Counters44) Explain what is storage and compute nodes?
The storage node is the machine or computer where your file system resides to store the processing data
The compute node is the computer or machine where your actual business logic will be executed.45) Mention what is the use of Context Object?
The Context Object enables the mapper to interact with the rest of the Hadoop
system. It includes configuration data for the job, as well as interfaces which allow it to emit output.46) Mention what is the next step after Mapper or MapTask?
The next step after Mapper or MapTask is that the output of the Mapper are sorted, and partitions will be created for the output.47) Mention what is the number of default partitioner in Hadoop?
In Hadoop, the default partitioner is a “Hash” Partitioner.48) Explain what is the purpose of RecordReader in Hadoop? 49) Explain how is data partitioned before it is sent to the reducer if no custom partitioner is defined in Hadoop?
If no custom partitioner is defined in Hadoop, then a default partitioner computes a hash value for the key and assigns the partition based on the result.50) Explain what happens when Hadoop spawned 50 tasks for a job and one of the task failed?
It will restart the task again on some other TaskTracker if the task fails more than the defined limit.51) Mention what is the best way to copy files between HDFS clusters?
The best way to copy files between HDFS clusters is by using multiple nodes and the distcp command, so the workload is shared.52) Mention what is the difference between HDFS and NAS?
HDFS data blocks are distributed across local drives of all machines in a cluster while NAS data is stored on dedicated hardware.53) Mention how Hadoop is different from other data processing tools?
In Hadoop, you can increase or decrease the number of mappers without worrying about the volume of data to be processed.54) Mention what job does the conf class do?
Job conf class separate different jobs running on the same cluster. It does the job level settings such as declaring a job in a real environment.55) Mention what is the Hadoop MapReduce APIs contract for a key and value class?
For a key and value class, there are two Hadoop MapReduce APIs contract
The value must be defining the org.apache.hadoop.io.Writable interface
The key must be defining the org.apache.hadoop.io.WritableComparable interface56) Mention what are the three modes in which Hadoop can be run?
The three modes in which Hadoop can be run are
Pseudo distributed mode
Standalone (local) mode
Fully distributed mode57) Mention what does the text input format do?
The text input format will create a line object that is an hexadecimal number. The value is considered as a whole line text while the key is considered as a line object. The mapper will receive the value as ‘text’ parameter while key as ‘longwriteable’ parameter.58) Mention how many InputSplits is made by a Hadoop Framework?
Hadoop will make 5 splits
1 split for 64K files
2 split for 65mb files
2 splits for 127mb files59) Mention what is distributed cache in Hadoop?
Distributed cache in Hadoop is a facility provided by MapReduce framework. At the time of execution of the job, it is used to cache file. The Framework copies the necessary files to the slave node before the execution of any task at that node.60) Explain how does Hadoop Classpath plays a vital role in stopping or starting in Hadoop daemons?
Classpath will consist of a list of directories containing jar files to stop or start daemons.
These interview questions will also help in your viva(orals)
Introduction To Go Interview Questions And Answers
Web development, programming languages, Software testing & others
It supports something called the environment, adapting patterns.
Go as fast as far as its compilation time is concerned.
It has Built concurrency support and lightweight processes via goroutines, channels, and select statements.
Go supports Interfaces and Type embedding.
Now, if you are looking for a job that is related to Go, then you need to prepare for the 2023 Go Interview Questions. Every interview is different from the different job profiles, but still, to clear the interview, you need to have a good and clear knowledge of Go. Here, we have prepared the important Go Interview Questions and Answers, which will help you succeed in your interview.
Below are the 10 important 2023 Go Interview Questions and Answers that are frequently asked in an interview. These questions are divided into parts are as follows:Part 1 – Go Interview Questions (Basic)
Let us now have a look at the basic Interview Questions and Answers.Q1.What is the Go language, and what are its benefits?
Benefits: Mentioned in bullets point above in the introduction section.Q2.Explain what do you understand by static type variable declaration in the Go language?
Static type variable declaration provides confidence to the compiler that there is nothing but at least one variable that exists with the given name of its declared type. This helps the compiler proceeds for further compilation without requiring a variable’s complete detail. Usually, the meaning of a variable in Go is at the time of compilation. At the time of linking of the program, the Go compiler needs a formal variable declaration.Q3.What are the methods in Go?
Go language supports special types of functions. These are called methods. In method declaration syntax, something called a “receiver” is present, which is used to represent the function container. The above-defined receiver can be used to call a function using an operator who is denoted by “.”.Q4.Explain what a string is literal?
There are two forms of a string literal in Go language: –
Raw string literals type: In this case, the value of such literals are character sequences which are between backquotes ‘‘. The value of a string literal is the string consisting of the uninterrupted character between quotes.
Interpreted string literals type: It is denoted between double quotes, which are the standard syntax. The content between the double quotes that may not contain newline characters usually forms the literal value in this case.Q5. Explain what a package in the Go program is?
All GO programs are made up of nothing but packages. The program that starts running in a package is called the main.Part 2 – Go Interview Questions (Advanced) Q6. Define what you understand from a workspace in GO Language?
Typically, a workspace is what keeps all of the Go source code. A workspace is a directory on your system hierarchy that contains three additional directories at the root position.
src – this contains GO source files organized into packages
pkg – this contains package objects and
bin – this contains executable commands
src, pkg and bin are folder structure which organizes the source code.
GO compiles very fast.
Go has concurrency support.
Functions are Go’s first-class objects.
GO supports garbage collection.
Strings and Maps are inbuilt into the language.
Let us move to the next Go Interview Questions.Q8. Explain a routine in GO? What method is used to stop goroutine?
A goroutine is a function that runs with other functions in concurrent mode. To stop go routine, pass the goroutine as a signal channel; this signal channel can be used to push a new value into the program when you want the goroutine to stop. The goroutine polls that channel regularly promptly as it finds a signal; it exists.Q9. Explain the Syntax For ‘for’ Loop?
Explanation: – The control flow in a for a loop –
If a condition is available, then for loop executes until the condition is true; this step is the same as any other language.
After the main statement of the for loop executes correctly, the program’s flow of control jumps goes back up to the next line, which is an increment statement. This statement does nothing, but it updates any loop control variables. This statement can be left blank if needed if a semicolon comes after the condition. The next condition is now checked again and then evaluated. If a condition is true, the loop runs once more, and the process repeats itself, i.e. the general approach is first to run the body of a loop, then increment step is done, and then again condition is executed. This continues until the condition becomes false and the loop terminates.
If a range is also given, then for loop runs for each value in the range. These are the frequently asked Go interview questions in an interview.Q10. By how many ways a parameter can be passed to a defined method in the Go language?
When calling a function in Go, there are two ways to pass an argument to a function such as: –
Call by value: This method works by copying an argument’s actual value into the function’s formal parameter. Thus, changes made to the function’s inside parameter do not have an effect on the argument.
Call by reference: This method works by copying the argument address into the formal parameter. The address is used inside the function for accessing the given argument used in the call. It means that parameter changes are made in this way affect the argument.Recommended Articles
This has been a guide to List Of Go Interview Questions and Answers so that the candidate can crackdown these Interview Questions easily. Here in this post, we have studied top Go Interview Questions, which are often asked in interviews. You may also look at the following articles to learn more –
Here are R Programming interview questions and answers for fresher as well experienced candidates to get their dream job.1) Explain what is R?
R is data analysis software which is used by analysts, quants, statisticians, data scientists and others.2) List out some of the function that R provides?
The function that R provides are
3) Explain how you can start the R commander GUI?
Typing the command, (“Rcmdr”) into the R console starts the R commander GUI.4) In R how you can import Data?
You use R commander to import Data in R, and there are three ways through which you can enter data into it
You can enter data directly via Data New Data Set
Import data from a plain text (ASCII) or other files (SPSS, Minitab, etc.)
Read a data set either by typing the name of the data set or selecting the data set in the dialog box5) Mention what does not ‘R’ language do?
Though R programming can easily connects to DBMS is not a database
R does not consist of any graphical user interface6) Explain how R commands are written?
In R, anywhere in the program you have to preface the line of code with a #sign, for example
# note order of operations exists7) How can you save your data in R?
To save data in R, there are many ways, but the easiest way of doing this is8) Mention how you can produce co-relations and covariances?
You can produce co-relations by the cor () function to produce co-relations and cov () function to produce covariances.9) Explain what is t-tests in R? 10) Explain what is With () and By () function in R is used for?
With() function is similar to DATA in SAS, it apply an expression to a dataset.
BY() function applies a function to each level of factors. It is similar to BY processing in SAS.11) What are the data structures in R that is used to perform statistical analyses and create graphs?
R has data structures like
Data frames12) Explain general format of Matrices in R?
General format isMymatrix< - matrix (vector, nrow=r , ncol=c , byrow=FALSE, dimnames = list ( char_vector_ rowname, char_vector_colnames)) 13) In R how missing values are represented ?
In R missing values are represented by NA (Not Available), why impossible values are represented by the symbol NaN (not a number).14) Explain what is transpose? 15) Explain how data is aggregated in R?
By collapsing data in R by using one or more BY variables, it becomes easy. When using the aggregate() function the BY variable should be in the list.16) What is the function used for adding datasets in R?
rbind function can be used to join two data frames (datasets). The two data frames must have the same variables, but they do not have to be in the same order.17) What is the use of subset() function and sample() function in R ?
In R, subset() functions help you to select variables and observations while through sample() function you can choose a random sample of size n from a dataset.18) Explain how you can create a table in R without external file?
Use the codemyTable = data.frame() edit(myTable)
These interview questions will also help in your viva(orals)
Following is a list of Agile Testing interview questions and answers, which are likely to be asked during the interview.
When requirement keeps changing, continuously agile tester should take following approach
Write generic test plans and test cases, which focuses on the intent of the requirement rather than its exact details
To understand the scope of change, work closely with the product owners or business analyst
Make sure team understand the risks involved in changing requirements especially at the end of the sprint
Until the feature is stable, and the requirements are finalized, it is best to wait if you are going to automate the feature
Changes can be kept to a minimum by negotiating or implement the changes in the next sprint2) List out the pros and cons of exploratory testing (used in Agile) and scripted testing?
Exploratory Testing – It requires less preparation- Easy to modify when requirement changes- Works well when documentation is scarce – Presenting progress and Coverage to project management is difficult
Scripted Testing – In case testing against legal or regulatory requirements it is very useful – Test preparation is usually time-consuming- Same steps are tested over and again- When requirement changes it is difficult to modify3) Explain the difference between Extreme programming and Scrum?
Scrum Extreme Programing (XP)
– Scrum teams usually have to work in iterations called sprints which usually last up to two weeks to one month long – XP team works in iteration that last for one or two weeks
– Scrum teams do not allow change into their sprints – XP teams are more flexible and change their iterations
– In scrum, the product owner prioritizes the product backlog but the team decides the sequence in which they will develop the backlog items – XP team work in strict priority order, features developed are prioritized by the customer
– Scrum does not prescribe any engineering practices – XP does prescribe engineering practices
4) What is an epic, user stories and task?
Epic: A customer described software feature that is itemized in the product backlog is known as epic. Epics are sub-divided into stories
User Stories: From the client perspective user stories are prepared which defines project or business functions, and it is delivered in a particular sprint as expected.
Task: Further down user stories are broken down into different task5) Explain what is re-factoring?
To improve the performance, the existing code is modified; this is re-factoring. During re-factoring the code functionality remains same6) Explain how you can measure the velocity of the sprint with varying team capacity?
When planning a sprint usually, the velocity of the sprint is measured on the basis of professional judgement based on historical data. However, the mathematical formula used to measure the velocity of the sprint are,
first – completed story points X team capacity: If you measure capacity as a percentage of a 40 hours weeks
Second – completed story points / team capacity: If you measure capacity in man-hours
For our scenario second method is applicable.7) Mention the key difference between sprint backlog and product backlog?
Product backlog: It contains a list of all desired features and is owned by the product owner.
Sprint backlog: It is a subset of the product backlog owned by development team and commits to deliver it in a sprint. It is created in Sprint Planning Meeting8) In Agile mention what is the difference between the Incremental and Iterative development?
Iterative: Iterative method is a continuous process of software development where the software development cycles are repeated (Sprint & Releases) till the final product is achieved.
Release 1: Sprint 1, 2… n
Release n: Sprint 1, 2….n9) Explain what is Spike and Zero sprint in Agile? What is the purpose of it?
Sprint Zero: It is introduced to perform some research before initiating the first sprint. Usually this sprint is used during the start of the project for activities like setting development environment, preparing product backlog and so on.
Spikes: Spikes are type of stories that are used for activities like research, exploration, design and even prototyping. In between sprints, you can take spikes for the work related to any technical or design issue. Spikes are of two types Technical Spikes and Functional Spikes.10) What is test driven development?
Test driven development or TDD is also known as test-driven design. In this method, developer first writes an automated test case which describes new function or improvement and then creates small codes to pass that test, and later re-factors the new code to meet the acceptable standards.11) Prototypes and Wireframes are widely used as part of?
Prototypes and Wireframes are prototypes that are widely used as part of Empirical Design.12) Explain what is Application Binary Interface?
Across different system platforms and environments a specification defining requirements for portability of applications in binary form is known as Application Binary Interface.13) Explain in Agile, burn-up and burn-down chart?
To track the project progress burnup and burn down, charts are used.
Burnup Chart: It shows the progress of stories done over time.
Burndown Chart: It shows how much work was left to do overtime.14) Explain what is Scrum ban?
Scrum ban is a software development model based on Scrum and Kanban. It is specially designed for project that requires frequent maintenance, having unexpected user stories and programming errors. Using these approach, the team’s workflow is guided in a way that allows minimum completion time for each user story or programming error.15) What is story points/efforts/ scales? 16) Explain what is tracer bullet?
The tracer bullet is a spike with the current architecture, the current set of best practices, current technology set which results in production quality code. It is not a throw away code but might just be a narrow implementation of the functionality.17) What is a test stub?
A test stub is a small code that replaces an undeveloped or fully developed component within a system being tested. Test stub is designed in such a way that it mimics the actual component by generating specifically known outputs and substitute the actual component.18) What are the differences between RUP (Rational Unified Process) and Scrum methodologies?
– Formal Cycle is defined across four phases, but some workflows can be concurrent – Each sprint is a complete cycle
– Formal project plan, associated with multiple iterations is used. – No end to end project plan. Each next iteration plan is determined at the end of the current iteration
– Scope is predefined ahead of the project start and documented in the scope document. During the project, scope can be revised. – It uses a project backlog instead of scope scrum
– Artifacts include Scope Document, formal functional requirements package, system architecture document, development plan, test scripts, etc. – Operational software is the only formal artifacts
– Recommended for long term, large, enterprise level projects with medium to high complexity – Recommended for quick enhancements and organization that are not dependent on a deadline19) Why Continuous Integration is important for Agile?
Continuous Integration is important for Agile for following reasons.
It helps to maintain release schedule on time by detecting bugs or integration errors
Due to frequent agile code delivery usually every sprint of 2-3 weeks, stable quality of build is a must and continuous integration ensures that
In helps to maintain the quality and bug free state of code-base
Continuous integration helps to check the impact of work on branches to the main trunk if development work is going on branches using automatic building and merging function20) What testing is done during Agile?
The primary testing activities during Agile is automated unit testing and exploratory testing.
Though, depending on project requirements, a tester may execute Functional and Non-functional tests on the Application Under Test (AUT).21) Explain what is Velocity in Agile?
Velocity is a metric that is calculated by addition of all efforts estimates related with user stories completed in an iteration. It figures out how much work Agile can complete in a sprint and how much time will it need to finish a project.22) What are the qualities of a good Agile tester should have?
A good Agile tester should have following qualities
It should be able to understand the requirements quickly
Agile tester should know Agile principals and concepts well
As requirements keep changing, tester should understand the risk involve in it
Based on the requirements Agile tester should be able to prioritize the work
Continue communication between business associates, developers and tester is must23) Who are all involved in the Agile team?
Scrum Masters: It coordinates most of the inputs and outputs required for an agile program
Development Managers: They hire right people and develop them with the team24) Mention in detail what are the role’s of Scrum Master?
Scrum Master key responsibilities involves
Understand the requirements and turn them into working software
Monitoring and Tracking
Reporting and Communication
Process Check Master
Shield the team and performance feedback
Lead all the meetings and resolve obstacles25) Mention what are the Agile quality strategies?
Agile quality strategies are
Static and dynamic code analysis
Reviews and Inspection
All hands demo
Light weight milestone reviews
Short feedback cycles
Standards and guidelines26) Mention what are the Tools that can be useful for screenshots while working on Agile projects?
While working on Agile projects you can use tools like
It helps team to objectively measure progress
It provides a consistent means of measuring team velocity
It helps to establish a consistent pattern of delivery28) If a timebox plan needs to be reprioritized who should re-prioritise it?
If a timebox plan needs to be reprioritized it should include whole team, product owner, and developers.29) Mention what should a burndown chart should highlight?
The burn-down chart shows the remaining work to complete before the timebox (iteration) ends.30) Mention what is the difference between Scrum and Agile?
Scrum: In the scrum, a sprint is a basic unit of development. Each sprint is followed by a planning meeting, where the tasks for the sprint are identified and estimated. During each sprint, the team creates finished portion of a product
Agile: In Agile, each iteration involves a team working through a full software development cycle, including planning, design, coding, requirement analysis, unit testing, and acceptance testing when a product is demonstrated to stakeholders
In simple words, Agile is the practice and scrum is the process to following this practice.31) Mention what are the challenges involved in AGILE software development?
Challenges involved in Agile Software development includes
It requires more testing and customers involvement
It impacts management more than developers
Each feature needs to be completed before moving on to the next
All the code has to work fine to ensure application is in working state
More planning is required32) When not to use Agile?
Before using Agile methodology, you must ask following questions
Is functionality split-able
Is customer available
Are requirements flexible
Is it really time constrained
Is team skilled enough33) Explain how can you implement scrum in an easy way to your project?
These are the tips which can be helpful to implement scrum in your project.
Get your backlog in order
Get an idea of the size of your product backlog items
Clarify sprint requirement and duration to complete the sprint backlog
Calculate the team sprint budget and then break requirements into tasks
Collaborate workspace- a center of all team discussion, which includes plans, roadmaps, key dates, sketches of functionality, issues, log, status reports, etc.
Sprint- Make sure you complete one feature at a time before moving on to the next. A sprint should not be abort unless if there is no other option
Attend a daily stand-up meeting: In meeting you need to mention, what have been achieved since the last meeting, what will they achieve before the next meeting and is anything holding up their progress
Use burndown chart to track daily progress. From the burndown chart, you can estimate whether you are on track, or you are running behind
Complete each features well before moving on to the next
At the end of the sprint- hold a sprint review meeting, mention what is achieved or delivered in the sprint.34) Explain what does it mean by product roadmap?
A product roadmap is referred for the holistic view of product features that create the product vision.
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