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?
Source: medium.
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?
Source: medium.
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🌟 Top 10 Java Frameworks You Should Know 🌟
Here’s a quick guide to the most popular Java frameworks every developer should explore:
1️⃣ Spring: A powerful, versatile framework for building web applications and enterprise-level projects.
2️⃣ Hibernate: Simplifies database operations with its ORM (Object Relational Mapping) capabilities.
3️⃣ Struts: Ideal for creating scalable and maintainable enterprise-ready Java web applications.
4️⃣ Google Web Toolkit (GWT): Perfect for creating complex browser-based applications, especially with Java-to-JavaScript compilation.
5️⃣ JavaServer Faces (JSF): Simplifies web app development by connecting UI components to server-side data.
6️⃣ Grails: A Groovy-based framework designed for simplifying Java app development.
7️⃣ Vaadin: Focuses on modern web application development with an appealing UI and seamless integration.
8️⃣ Blade: A lightweight and high-performance framework for building fast REST APIs.
9️⃣ Dropwizard: Combines libraries to quickly create reliable, production-ready applications.
🔟 Play: A reactive web application framework that supports both Java and Scala.
💡 Explore these frameworks to stay ahead in your Java development journey! 🚀
#JavaFrameworks
Here’s a quick guide to the most popular Java frameworks every developer should explore:
1️⃣ Spring: A powerful, versatile framework for building web applications and enterprise-level projects.
2️⃣ Hibernate: Simplifies database operations with its ORM (Object Relational Mapping) capabilities.
3️⃣ Struts: Ideal for creating scalable and maintainable enterprise-ready Java web applications.
4️⃣ Google Web Toolkit (GWT): Perfect for creating complex browser-based applications, especially with Java-to-JavaScript compilation.
5️⃣ JavaServer Faces (JSF): Simplifies web app development by connecting UI components to server-side data.
6️⃣ Grails: A Groovy-based framework designed for simplifying Java app development.
7️⃣ Vaadin: Focuses on modern web application development with an appealing UI and seamless integration.
8️⃣ Blade: A lightweight and high-performance framework for building fast REST APIs.
9️⃣ Dropwizard: Combines libraries to quickly create reliable, production-ready applications.
🔟 Play: A reactive web application framework that supports both Java and Scala.
💡 Explore these frameworks to stay ahead in your Java development journey! 🚀
#JavaFrameworks
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5⃣ Free DSA resources to crack coding interview
👉 GeekforGeeks
https://www.geeksforgeeks.org/the-ultimate-beginners-guide-for-dsa/amp/
👉 Leetcode
https://leetcode.com/study-plan/data-structure/
👉 Hackerrank
https://www.hackerrank.com/domains/data-structures
👉 Coding Interview Preparations
https://t.me/crackingthecodinginterview/112
👉 FreeCodeCamp
https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/
Join @free4unow_backup for more free courses
ENJOY LEARNING 👍👍
👉 GeekforGeeks
https://www.geeksforgeeks.org/the-ultimate-beginners-guide-for-dsa/amp/
👉 Leetcode
https://leetcode.com/study-plan/data-structure/
👉 Hackerrank
https://www.hackerrank.com/domains/data-structures
👉 Coding Interview Preparations
https://t.me/crackingthecodinginterview/112
👉 FreeCodeCamp
https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/
Join @free4unow_backup for more free courses
ENJOY LEARNING 👍👍
❤5👎1
List of Java Project Ideas 💡👨🏻💻☕
Beginner Projects
🔹 Calculator
🔹 To-Do List App
🔹 Number Guessing Game
🔹 Password Generator
🔹 Flashcard Quizzer
🔹 Simple Chatbot
🔹 Weather App
🔹 Unit Converter
🔹 Rock-Paper-Scissors Game
Intermediate Projects
🔸 Personal Diary
🔸 Web Scraping Tool
🔸 Expense Tracker
🔸 Spring Boot Blog
🔸 Image Gallery
🔸 Chat Application
🔸 Pomodoro Timer
🔸 Basic Game with JavaFX
Advanced Projects
🔺 Social Media Dashboard
🔺 Machine Learning Model
🔺 Data Visualization Tool
🔺 Blockchain Simulation
🔺 Chatbot with NLP
🔺 File Organizer
Free Java Resources: https://t.me/Java_Programming_Notes
Beginner Projects
🔹 Calculator
🔹 To-Do List App
🔹 Number Guessing Game
🔹 Password Generator
🔹 Flashcard Quizzer
🔹 Simple Chatbot
🔹 Weather App
🔹 Unit Converter
🔹 Rock-Paper-Scissors Game
Intermediate Projects
🔸 Personal Diary
🔸 Web Scraping Tool
🔸 Expense Tracker
🔸 Spring Boot Blog
🔸 Image Gallery
🔸 Chat Application
🔸 Pomodoro Timer
🔸 Basic Game with JavaFX
Advanced Projects
🔺 Social Media Dashboard
🔺 Machine Learning Model
🔺 Data Visualization Tool
🔺 Blockchain Simulation
🔺 Chatbot with NLP
🔺 File Organizer
Free Java Resources: https://t.me/Java_Programming_Notes
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