Typical java interview questions sorted by experience
Junior
* Name some of the characteristics of OO programming languages
* What are the access modifiers you know? What does each one do?
* What is the difference between overriding and overloading a method in Java?
* What’s the difference between an Interface and an abstract class?
* Can an Interface extend another Interface?
* What does the static word mean in Java?
* Can a static method be overridden in Java?
* What is Polymorphism? What about Inheritance?
* Can a constructor be inherited?
* Do objects get passed by reference or value in Java? Elaborate on that.
* What’s the difference between using == and .equals on a string?
* What is the hashCode() and equals() used for?
* What does the interface Serializable do? What about Parcelable in Android?
* Why are Array and ArrayList different? When would you use each?
* What’s the difference between an Integer and int?
* What is a ThreadPool? Is it better than using several “simple” threads?
* What the difference between local, instance and class variables?
Mid
* What is reflection?
* What is dependency injection? Can you name a few libraries? (Have you used any?)
* What are strong, soft and weak references in Java?
* What does the keyword synchronized mean?
* Can you have “memory leaks” on Java?
* Do you need to set references to null on Java/Android?
* What does it means to say that a String is immutable?
* What are transient and volatile modifiers?
* What is the finalize() method?
* How does the try{} finally{} works?
* What is the difference between instantiation and initialisation of an object?
* When is a static block run?
* Why are Generics are used in Java?
* Can you mention the design patterns you know? Which of those do you normally use?
* Can you mention some types of testing you know?
Senior
* How does Integer.parseInt() works?
* Do you know what is the “double check locking” problem?
* Do you know the difference between StringBuffer and StringBuilder?
* How is a StringBuilder implemented to avoid the immutable string allocation problem?
* What does Class.forName method do?
* What is Autoboxing and Unboxing?
* What’s the difference between an Enumeration and an Iterator?
* What is the difference between fail-fast and fail safe in Java?
* What is PermGen in Java?
* What is a Java priority queue?
* *s performance influenced by using the same number in different types: Int, Double and Float?
* What is the Java Heap?
* What is daemon thread?
* Can a dead thread be restarted?
You can check these resources for Coding interview Preparation
All the best 👍👍
Junior
* Name some of the characteristics of OO programming languages
* What are the access modifiers you know? What does each one do?
* What is the difference between overriding and overloading a method in Java?
* What’s the difference between an Interface and an abstract class?
* Can an Interface extend another Interface?
* What does the static word mean in Java?
* Can a static method be overridden in Java?
* What is Polymorphism? What about Inheritance?
* Can a constructor be inherited?
* Do objects get passed by reference or value in Java? Elaborate on that.
* What’s the difference between using == and .equals on a string?
* What is the hashCode() and equals() used for?
* What does the interface Serializable do? What about Parcelable in Android?
* Why are Array and ArrayList different? When would you use each?
* What’s the difference between an Integer and int?
* What is a ThreadPool? Is it better than using several “simple” threads?
* What the difference between local, instance and class variables?
Mid
* What is reflection?
* What is dependency injection? Can you name a few libraries? (Have you used any?)
* What are strong, soft and weak references in Java?
* What does the keyword synchronized mean?
* Can you have “memory leaks” on Java?
* Do you need to set references to null on Java/Android?
* What does it means to say that a String is immutable?
* What are transient and volatile modifiers?
* What is the finalize() method?
* How does the try{} finally{} works?
* What is the difference between instantiation and initialisation of an object?
* When is a static block run?
* Why are Generics are used in Java?
* Can you mention the design patterns you know? Which of those do you normally use?
* Can you mention some types of testing you know?
Senior
* How does Integer.parseInt() works?
* Do you know what is the “double check locking” problem?
* Do you know the difference between StringBuffer and StringBuilder?
* How is a StringBuilder implemented to avoid the immutable string allocation problem?
* What does Class.forName method do?
* What is Autoboxing and Unboxing?
* What’s the difference between an Enumeration and an Iterator?
* What is the difference between fail-fast and fail safe in Java?
* What is PermGen in Java?
* What is a Java priority queue?
* *s performance influenced by using the same number in different types: Int, Double and Float?
* What is the Java Heap?
* What is daemon thread?
* Can a dead thread be restarted?
You can check these resources for Coding interview Preparation
All the best 👍👍
👍3❤2
Java project ideas to help you practice your skills
1. ToDo List Application: Create a command-line or GUI-based application that allows users to create, manage, and organize their tasks.
2. Calculator: Build a simple calculator application that can perform basic arithmetic operations like addition, subtraction, multiplication, and division.
3. Library Management System: Design a system for managing library resources, including books, patrons, and borrowing records.
4. Chat Application: Develop a chat application that enables users to communicate in real-time, either as a desktop app or through a web interface.
5. Weather App: Create an app that fetches weather data from an API and displays current weather conditions for a given location.
6. Student Gradebook: Build a program to store and calculate student grades. You can add features like grade averages and report generation.
7. Expense Tracker: Create an application for tracking expenses and generating reports, helping users manage their finances.
8. Simple Game (e.g., Tic-Tac-Toe): Implement a classic game like Tic-Tac-Toe to learn about game logic and user interaction.
9. Blog or Content Management System (CMS): Build a simple blog or CMS where users can create, edit, and publish articles.
10. E-commerce Shopping Cart: Create a basic online shopping cart system with product listings, a shopping cart, and checkout functionality.
11. File Manager: Develop a file manager application that allows users to organize and manage files and directories on their computer.
12. Inventory System: Design an inventory management system for tracking products, quantities, and orders for a small business.
13. Music Player: Create a basic music player with features like play, pause, skip, and a library of songs.
14. Password Manager: Build a secure application for storing and managing passwords and other sensitive information.
15. Chess or Sudoku Solver: Implement a chess game or a Sudoku puzzle solver to delve into complex algorithms and logic.
16. Note-taking App: Develop a note-taking application with features like creating, editing, and organizing notes.
17. Expense Sharing App: Build an app for groups to track shared expenses and split bills among friends or roommates.
18. Task Scheduler: Create a program that allows users to schedule and manage tasks, reminders, and appointments.
19. Mini Social Media Platform: Create a simplified social media platform with features like user profiles, posting, and commenting.
20. Quiz or Flashcard Application: Design an app for creating and taking quizzes or using flashcards to study various topics.
Choose a project that aligns with your interests and skill level. As you work on these projects, you'll gain valuable experience and improve your Java programming skills.
1. ToDo List Application: Create a command-line or GUI-based application that allows users to create, manage, and organize their tasks.
2. Calculator: Build a simple calculator application that can perform basic arithmetic operations like addition, subtraction, multiplication, and division.
3. Library Management System: Design a system for managing library resources, including books, patrons, and borrowing records.
4. Chat Application: Develop a chat application that enables users to communicate in real-time, either as a desktop app or through a web interface.
5. Weather App: Create an app that fetches weather data from an API and displays current weather conditions for a given location.
6. Student Gradebook: Build a program to store and calculate student grades. You can add features like grade averages and report generation.
7. Expense Tracker: Create an application for tracking expenses and generating reports, helping users manage their finances.
8. Simple Game (e.g., Tic-Tac-Toe): Implement a classic game like Tic-Tac-Toe to learn about game logic and user interaction.
9. Blog or Content Management System (CMS): Build a simple blog or CMS where users can create, edit, and publish articles.
10. E-commerce Shopping Cart: Create a basic online shopping cart system with product listings, a shopping cart, and checkout functionality.
11. File Manager: Develop a file manager application that allows users to organize and manage files and directories on their computer.
12. Inventory System: Design an inventory management system for tracking products, quantities, and orders for a small business.
13. Music Player: Create a basic music player with features like play, pause, skip, and a library of songs.
14. Password Manager: Build a secure application for storing and managing passwords and other sensitive information.
15. Chess or Sudoku Solver: Implement a chess game or a Sudoku puzzle solver to delve into complex algorithms and logic.
16. Note-taking App: Develop a note-taking application with features like creating, editing, and organizing notes.
17. Expense Sharing App: Build an app for groups to track shared expenses and split bills among friends or roommates.
18. Task Scheduler: Create a program that allows users to schedule and manage tasks, reminders, and appointments.
19. Mini Social Media Platform: Create a simplified social media platform with features like user profiles, posting, and commenting.
20. Quiz or Flashcard Application: Design an app for creating and taking quizzes or using flashcards to study various topics.
Choose a project that aligns with your interests and skill level. As you work on these projects, you'll gain valuable experience and improve your Java programming skills.
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🔟 unique web development project ideas for freshers
1. Freelance Client Management System:
Build a system for freelancers to track client details, project timelines, invoices, and payments. Incorporate features like task lists, payment reminders, and time tracking. You’ll get hands-on experience with CRUD operations and secure user authentication.
2. Nonprofit Donation Platform:
Develop a platform for nonprofit organizations where users can donate to causes. You can include a donation tracker, goal setting, and integration with payment gateways like Stripe or PayPal. This will involve front-end design and server-side payment processing.
3. Interactive Educational Platform for Kids:
Create a platform where kids can learn basic subjects like math, spelling, or coding through fun, interactive games. Add features like badges, scoreboards, and quizzes to keep them engaged. This will give you experience in animations, gamification, and user experience design.
4. Real Estate Listings Website:
Build a platform where agents or homeowners can list properties for rent or sale. Include features like advanced search, map integration, and filters for property type, price, and location. You’ll get exposure to working with APIs and map services like Google Maps.
5. Virtual Art Gallery:
Design a virtual space where artists can display their work. Use animations to simulate a walk-through gallery, allowing users to explore and click on individual pieces for more details. You’ll explore 3D rendering, animations, and responsive design in this project.
6. Job Application Tracker:
Help job seekers keep track of job applications by building a dashboard that organizes companies, positions, interview stages, and deadlines. This app could send automated reminders for follow-ups, giving you experience with notifications and task scheduling.
7. Music Streaming Player:
Develop a personalized music player where users can create and share playlists. Integrate it with a music API like Spotify or Apple Music to pull in tracks. This project will introduce you to audio streaming, user authentication, and data storage for playlists.
8. Mental Health Tracker:
Create a web app where users can log daily moods, set mental health goals, and track progress over time. Incorporate features like journaling, breathing exercises, and visual data charts. This would involve data collection, chart visualization, and user interface design.
9. Sustainable Shopping Guide:
Build a platform where users can discover eco-friendly products and businesses. You can integrate a rating system for users to rate brands on sustainability practices. The project will teach you about APIs, user-generated content, and social proof.
10. Virtual Study Group App:
Create an app where students can join or form virtual study groups, chat in real-time, and share resources like notes and flashcards. You can add video integration or virtual whiteboards to make the platform more collaborative. This project will help you understand real-time data transfer, group authentication, and video/chat APIs.
Web Development Best Resources: https://topmate.io/coding/930165
ENJOY LEARNING 👍👍
1. Freelance Client Management System:
Build a system for freelancers to track client details, project timelines, invoices, and payments. Incorporate features like task lists, payment reminders, and time tracking. You’ll get hands-on experience with CRUD operations and secure user authentication.
2. Nonprofit Donation Platform:
Develop a platform for nonprofit organizations where users can donate to causes. You can include a donation tracker, goal setting, and integration with payment gateways like Stripe or PayPal. This will involve front-end design and server-side payment processing.
3. Interactive Educational Platform for Kids:
Create a platform where kids can learn basic subjects like math, spelling, or coding through fun, interactive games. Add features like badges, scoreboards, and quizzes to keep them engaged. This will give you experience in animations, gamification, and user experience design.
4. Real Estate Listings Website:
Build a platform where agents or homeowners can list properties for rent or sale. Include features like advanced search, map integration, and filters for property type, price, and location. You’ll get exposure to working with APIs and map services like Google Maps.
5. Virtual Art Gallery:
Design a virtual space where artists can display their work. Use animations to simulate a walk-through gallery, allowing users to explore and click on individual pieces for more details. You’ll explore 3D rendering, animations, and responsive design in this project.
6. Job Application Tracker:
Help job seekers keep track of job applications by building a dashboard that organizes companies, positions, interview stages, and deadlines. This app could send automated reminders for follow-ups, giving you experience with notifications and task scheduling.
7. Music Streaming Player:
Develop a personalized music player where users can create and share playlists. Integrate it with a music API like Spotify or Apple Music to pull in tracks. This project will introduce you to audio streaming, user authentication, and data storage for playlists.
8. Mental Health Tracker:
Create a web app where users can log daily moods, set mental health goals, and track progress over time. Incorporate features like journaling, breathing exercises, and visual data charts. This would involve data collection, chart visualization, and user interface design.
9. Sustainable Shopping Guide:
Build a platform where users can discover eco-friendly products and businesses. You can integrate a rating system for users to rate brands on sustainability practices. The project will teach you about APIs, user-generated content, and social proof.
10. Virtual Study Group App:
Create an app where students can join or form virtual study groups, chat in real-time, and share resources like notes and flashcards. You can add video integration or virtual whiteboards to make the platform more collaborative. This project will help you understand real-time data transfer, group authentication, and video/chat APIs.
Web Development Best Resources: https://topmate.io/coding/930165
ENJOY LEARNING 👍👍
👍6❤2
Don't overwhelm to learn Git,🙌
Git is only this much👇😇
1.Core:
• git init
• git clone
• git add
• git commit
• git status
• git diff
• git checkout
• git reset
• git log
• git show
• git tag
• git push
• git pull
2.Branching:
• git branch
• git checkout -b
• git merge
• git rebase
• git branch --set-upstream-to
• git branch --unset-upstream
• git cherry-pick
3.Merging:
• git merge
• git rebase
4.Stashing:
• git stash
• git stash pop
• git stash list
• git stash apply
• git stash drop
5.Remotes:
• git remote
• git remote add
• git remote remove
• git fetch
• git pull
• git push
• git clone --mirror
6.Configuration:
• git config
• git global config
• git reset config
7. Plumbing:
• git cat-file
• git checkout-index
• git commit-tree
• git diff-tree
• git for-each-ref
• git hash-object
• git ls-files
• git ls-remote
• git merge-tree
• git read-tree
• git rev-parse
• git show-branch
• git show-ref
• git symbolic-ref
• git tag --list
• git update-ref
8.Porcelain:
• git blame
• git bisect
• git checkout
• git commit
• git diff
• git fetch
• git grep
• git log
• git merge
• git push
• git rebase
• git reset
• git show
• git tag
9.Alias:
• git config --global alias.<alias> <command>
10.Hook:
• git config --local core.hooksPath <path>
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https://t.iss.one/addlist/4q2PYC0pH_VjZDk5
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Git is only this much👇😇
1.Core:
• git init
• git clone
• git add
• git commit
• git status
• git diff
• git checkout
• git reset
• git log
• git show
• git tag
• git push
• git pull
2.Branching:
• git branch
• git checkout -b
• git merge
• git rebase
• git branch --set-upstream-to
• git branch --unset-upstream
• git cherry-pick
3.Merging:
• git merge
• git rebase
4.Stashing:
• git stash
• git stash pop
• git stash list
• git stash apply
• git stash drop
5.Remotes:
• git remote
• git remote add
• git remote remove
• git fetch
• git pull
• git push
• git clone --mirror
6.Configuration:
• git config
• git global config
• git reset config
7. Plumbing:
• git cat-file
• git checkout-index
• git commit-tree
• git diff-tree
• git for-each-ref
• git hash-object
• git ls-files
• git ls-remote
• git merge-tree
• git read-tree
• git rev-parse
• git show-branch
• git show-ref
• git symbolic-ref
• git tag --list
• git update-ref
8.Porcelain:
• git blame
• git bisect
• git checkout
• git commit
• git diff
• git fetch
• git grep
• git log
• git merge
• git push
• git rebase
• git reset
• git show
• git tag
9.Alias:
• git config --global alias.<alias> <command>
10.Hook:
• git config --local core.hooksPath <path>
✅ Best Telegram channels to get free coding & data science resources
https://t.iss.one/addlist/4q2PYC0pH_VjZDk5
✅ Free Courses with Certificate:
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👍6❤1
Things that a Web Developer must know concerning database storage and management:
🟡Characteristics of relational/non-relational data.
🟡Knowledge of NoSQL databases.
🟡Knowledge of web storage.
Following are some of the best databases you must learn
🟧Relational databases: Within the tables, data is stored in rows and columns. The relational database management system (RDBMS) is the program that allows you to create, update, and administer a relational database. Microsoft SQL Server, Oracle Database, MySQL, PostgreSQL, and IBM Db2 are examples of rational databases.
🟧NoSQL: NoSQL databases (aka “not only SQL”) are non-tabular, and store data differently than relational tables. NoSQL databases come in a variety of types based on their data model. The main types are document, key-value, wide-column, and graph. Apache Cassandra, MongoDB, CouchDB, and Couchbase are examples of NoSQL.
🟧Cloud database: It refers to any database that’s designed to run in the cloud. Like other cloud-based applications, cloud databases offer flexibility and scalability, along with high availability. Cloud databases are also often low-maintenance since many are offered via a SaaS model. Microsoft Azure SQL Database, Amazon Relational Database Service, Oracle Autonomous Database are examples of cloud database..
⚡Technology Stacks- MEAN, MERN, MeVn, Lamp
🔰MEAN Stack: MEAN stack development refers to the development process that falls within these particular sets of technologies MongoDB, ExpressJS, Angular, NodeJS.
🔰MERN Stack: It is is one of several variations of the MEAN stack (MongoDB, Express, Angular, Node), where the traditional Angular frontend framework is replaced with React JS. The main benefit of using MERN is the integration of React and its powerful library and capability to use code simultaneously on servers and browsers.
🔰MEVN Stack: Other variants of MEAN Stack, the MEVN Stack (MongoDB, Express, Vue, Node), and really any frontend JavaScript framework can work. It is the open-source JavaScript software stack that has emerged as a new and evolving way to build powerful and dynamic web applications
🔰LAMP: It is an old classic industry standard when it comes to time-tested web development stacks, which comprises MySQL (Relational Database Management), Linux (Operating System), PHP (Programming Language), and Apache (HTTP server).
You can find more Web Development Resources here 👇👇
https://topmate.io/coding/930165
Share our telegram channel with your friends and family 👇👇
https://t.iss.one/webdevcoursefree
🟡Characteristics of relational/non-relational data.
🟡Knowledge of NoSQL databases.
🟡Knowledge of web storage.
Following are some of the best databases you must learn
🟧Relational databases: Within the tables, data is stored in rows and columns. The relational database management system (RDBMS) is the program that allows you to create, update, and administer a relational database. Microsoft SQL Server, Oracle Database, MySQL, PostgreSQL, and IBM Db2 are examples of rational databases.
🟧NoSQL: NoSQL databases (aka “not only SQL”) are non-tabular, and store data differently than relational tables. NoSQL databases come in a variety of types based on their data model. The main types are document, key-value, wide-column, and graph. Apache Cassandra, MongoDB, CouchDB, and Couchbase are examples of NoSQL.
🟧Cloud database: It refers to any database that’s designed to run in the cloud. Like other cloud-based applications, cloud databases offer flexibility and scalability, along with high availability. Cloud databases are also often low-maintenance since many are offered via a SaaS model. Microsoft Azure SQL Database, Amazon Relational Database Service, Oracle Autonomous Database are examples of cloud database..
⚡Technology Stacks- MEAN, MERN, MeVn, Lamp
🔰MEAN Stack: MEAN stack development refers to the development process that falls within these particular sets of technologies MongoDB, ExpressJS, Angular, NodeJS.
🔰MERN Stack: It is is one of several variations of the MEAN stack (MongoDB, Express, Angular, Node), where the traditional Angular frontend framework is replaced with React JS. The main benefit of using MERN is the integration of React and its powerful library and capability to use code simultaneously on servers and browsers.
🔰MEVN Stack: Other variants of MEAN Stack, the MEVN Stack (MongoDB, Express, Vue, Node), and really any frontend JavaScript framework can work. It is the open-source JavaScript software stack that has emerged as a new and evolving way to build powerful and dynamic web applications
🔰LAMP: It is an old classic industry standard when it comes to time-tested web development stacks, which comprises MySQL (Relational Database Management), Linux (Operating System), PHP (Programming Language), and Apache (HTTP server).
You can find more Web Development Resources here 👇👇
https://topmate.io/coding/930165
Share our telegram channel with your friends and family 👇👇
https://t.iss.one/webdevcoursefree
✍2👍2❤1🔥1
These are top 5 data structures and algorithms projects, allowing you to dive deep into the world of DSA 💪🏻
•Project 1: Snakes Game (Arrays)
The Snakes Game project is a classic implementation of the popular game
Snake.
This project allows you to understand the concepts of arrays, loops, and conditional statements. You can further enhance the game by incorporating additional features such as score tracking and power-ups.
•Project 2: Cash Flow Minimizer (Graphs/ Multisets/Heaps)
The Cash Flow Minimizer project involves solving a cash flow optimization problem using graphs, multisets, and heaps. Given a set of transactions among a group of people, the objective is to minimize the total number of transactions required to settle all debts
•Project 3: Sudoku Solver (Backtracking)
The Sudoku Solver project aims to solve the popular Sudoku puzzle using backtracking. This project allows you to understand the backtracking algorithm, which is widely used in solving constraint satisfaction problems.
•Project 4: File Zipper (Greedy Huffman
Encoder)
The File Zipper project focuses on implementing a file compression utility using the Greedy Huffman encoding algorithm. This project provides a practical application of the greedy algorithm and helps you understand the trade-offs between
compression ratio and execution time.
•Project 5: Map Navigator (Dijkstra’s
Algorithm)
The Map Navigator project aims to develop a navigation system using Dijkstra’s algorithm. It involves finding the shortest path between two locations on a map, considering factors such as distance and traffic.
You can check these amazing resources for DSA Preparation
Join for more: https://t.iss.one/crackingthecodinginterview
All the best 👍👍
•Project 1: Snakes Game (Arrays)
The Snakes Game project is a classic implementation of the popular game
Snake.
This project allows you to understand the concepts of arrays, loops, and conditional statements. You can further enhance the game by incorporating additional features such as score tracking and power-ups.
•Project 2: Cash Flow Minimizer (Graphs/ Multisets/Heaps)
The Cash Flow Minimizer project involves solving a cash flow optimization problem using graphs, multisets, and heaps. Given a set of transactions among a group of people, the objective is to minimize the total number of transactions required to settle all debts
•Project 3: Sudoku Solver (Backtracking)
The Sudoku Solver project aims to solve the popular Sudoku puzzle using backtracking. This project allows you to understand the backtracking algorithm, which is widely used in solving constraint satisfaction problems.
•Project 4: File Zipper (Greedy Huffman
Encoder)
The File Zipper project focuses on implementing a file compression utility using the Greedy Huffman encoding algorithm. This project provides a practical application of the greedy algorithm and helps you understand the trade-offs between
compression ratio and execution time.
•Project 5: Map Navigator (Dijkstra’s
Algorithm)
The Map Navigator project aims to develop a navigation system using Dijkstra’s algorithm. It involves finding the shortest path between two locations on a map, considering factors such as distance and traffic.
You can check these amazing resources for DSA Preparation
Join for more: https://t.iss.one/crackingthecodinginterview
All the best 👍👍
👍2