Java Interview Question 👇 Which is generally preferred for implementing a Stack in modern Java? A) `Vector` B) `Stack` C) ArrayDeque` D) LinkedList` ✅ Answer: `ArrayDeque` Read my latest ByteCraft article: 🔗 gauravrshegekar.substack.com/p/stack-in-j...? #Java #JavaDeveloper #Stack
Stack in Java
Last in, first out — the foundation of stack-based processing.
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🔥Think you know Java Queues? Queue<Integer> q = new PriorityQueue<>(); q.offer(30); q.offer(10); q.offer(20); System.out.println(q.poll()); What prints? Most say 30 (FIFO). Wrong. Answer: 10 Why? Read Blog here: gauravrshegekar.substack.com/p/priorityqu...? #Java #PriorityQueue
PriorityQueue in Java
Process elements based on priority, not arrival order.
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**Java Interview Question 👇** Is `PriorityQueue` a FIFO queue? ❌ No. A normal Queue generally follows: `FIFO → First In, First Out` But `PriorityQueue` processes elements according to their priority. Read my latest article on Queue in Java 🔗 gauravrshegekar.substack.com/p/queue-in-j...?
Queue in Java
Process data in the order it arrives.
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Which statement is correct? A) HashMap allows duplicate keys. B) HashMap maintains sorted order. C) HashMap stores key-value pairs and provides fast lookups. ✅ Answer: C In my latest ByteCraft article, I explain: 🔗 open.substack.com/pub/gauravrs... #Java #JavaDeveloper #HashMap
HashMap in Java
Store and retrieve key-value pairs with speed and efficiency.
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Which collection should you use if you need: ✅ Unique elements ✅ Automatic sorting 🤔 Answer: TreeSet Read my latest article: 🔗 open.substack.com/pub/gauravrs...? #Java #JavaDeveloper #TreeSet #Collections #Programming #SpringBoot #ByteCraft
TreeSet in Java
Store unique elements in a naturally sorted order.
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Gaurav Shegekar @GShegekar84152 · Now Why HashSet stores only unique elements? Read my latest article on HashSet 🔗 open.substack.com/pub/gauravrs... #Java #JavaDeveloper #HashSet #Collections #Programming #SpringBoot #ByteCraftWhy
HashSet in Java
Store unique elements efficiently with one of Java's fastest collections.
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Managing shared objects across an application? 🤔 Creating the same service in multiple places leads to duplication and tightly managed code. I just published a beginner-friendly guide on the **Registry Pattern** in Java. Read Here : open.substack.com/pub/gauravrs...? #Java #RegistryPattern
Registry Pattern
Managing Shared Objects from a Centralized Registry
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Which collection is better for frequent insertions and deletions? ✅ LinkedList But here's the catch... Why is LinkedList.get(index) still O(n)? 🤔 The answer lies in its internal node-based structure. Read my latest article : open.substack.com/pub/gauravrs...? #Java #JavaDeveloper
LinkedList in Java
Efficiently manage dynamic data with fast insertions and deletions.
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Creating complex objects from scratch every time? 🤔 There's a smarter way. I just published a beginner-friendly guide on the Prototype Design Pattern in Java. Read here : open.substack.com/pub/gauravrs...? #Java #SpringBoot #PrototypePattern #DesignPatterns #LLD #SystemDesign
Prototype Design Pattern
Creating Objects by Cloning Instead of Starting from Scratch
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Why is ArrayList.add() at the end O(1) amortized and not always O(1)? 🤔 The answer lies in how ArrayList grows internally. Read my latest article on ArrayList in Java open.substack.com/pub/gauravrs...? #Java #JavaDeveloper #ArrayList #Collections #Programming #SpringBoot #ByteCraft
ArrayList in Java
The most widely used List implementation for dynamic data storage.
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Which collection would you choose? 🛒 Shopping Cart → ? 🏷️ Unique Categories → ? 🆔 Product ID → Product → ? ✅ Answers: • List → Ordered data with duplicates • Set → Unique elements • Map → Key-value pairs In my latest article : 🔗 open.substack.com/pub/gauravrs... #Java #JavaDeveloper#Collections
List vs Set vs Map in Java
Choose the right collection for the right problem.
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Which one does NOT implement the Collection interface? A️-> List B️-> Set C️-> Queue D️->Map ✅ Answer: Map It's part of the Java Collections Framework, but it has its own hierarchy. Read my latest article on Collection Framework : open.substack.com/pub/gauravrs...? #Java #Collections #Programming
Collection Framework Overview in Java
Master Java's powerful framework for storing and managing data efficiently.
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Long constructors are a code smell. 👀 If you're passing 8–10 parameters to create an object, there's a better way. I just published a beginner-friendly guide on the Builder Design Pattern in Java. Read here : open.substack.com/pub/gauravrs...? A must-read for every Java & Spring Boot developer.
Builder Design Pattern
Creating Complex Objects the Right Way
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Why do Java package names usually look like this? com.company.project 🤔 Why not simply project? Read my latest article On Packages in Java 🔗 open.substack.com/pub/gauravrs...? #Java #JavaDeveloper #Programming #SpringBoot #BackendDevelopment #ByteCraft
Packages in Java
Organize your code for better structure, reusability, and maintainability.
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Which is the better approach? ❌ Manual finally block ✅ Try-With-Resources Why? Because Java automatically closes resources—even when exceptions occur. Read my latest article on Try-With-Resources in Java 🔗 open.substack.com/pub/gauravrs...? #Java #JavaDeveloper #ExceptionHandling #Programming
Try-With-Resources in Java
Manage resources automatically and prevent resource leaks with ease.
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Most developers know Java. Fewer know how to design software. Design Patterns help you write code that's easier to maintain, extend, and scale. Read my latest article on Design patterns : open.substack.com/pub/gauravrs...? #Java #DesignPatterns #Singleton #LLD
Design Patterns
The Foundation of Low-Level System Design
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Which is better? throw new IllegalArgumentException("Invalid"); OR throw new InsufficientBalanceException( "Insufficient account balance." ); ✅ The second. Read my latest article on Custom Exceptions open.substack.com/pub/gauravrs...? #Java #JavaDeveloper #ExceptionHandling #Programming
Custom Exceptions in Java
Create meaningful exceptions tailored to your business logic.
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I just published a beginner-friendly guide on the SOLID Principles with practical Java examples. ✔️ SRP ✔️ OCP ✔️ LSP ✔️ ISP ✔️ DIP Learn how to write code using SOLIDPrinciples Read Here : open.substack.com/pub/gauravrs... #Java #SpringBoot #CleanCode #SOLID #LLD #SystemDesign
SOLID Principles
Write Better Code That Scales
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Which of these is a Checked Exception? ✅ IOException or ✅ NullPointerException If you answered IOException, you're right. But do you know why Java treats them differently? Read my latest article on Checked vs Unchecked Exception open.substack.com/pub/gauravrs...? #Java #JavaDeveloper
Checked vs Unchecked Exception in Java
Understand the two types of exceptions every Java developer must know.
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What's the difference between: ✅ throw and ✅ throws? Many developers confuse the two. Read my latest article on Exception Handling 🔗https://open.substack.com/pub/gauravrshegekar/p/exception-handling-in-java? #Java #JavaDeveloper #ExceptionHandling #Programming #SpringBoot #ByteCraft
What's the output? final List<String> list = new ArrayList<>(); list.add("Java"); 🤔 Compilation Error or Runs Successfully? The answer surprises many beginners. Read my latest article on Final Keyword in Java 🔗 open.substack.com/pub/gauravrs...? #Java #JavaDeveloper #Programming
Final Keyword in Java
Prevent modification and write safer, more predictable Java code.
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Which statement is true? A️-> this refers to the current object. B -> super refers to the parent object. ✅ The answer is Both but they serve different purposes. Read my latest article on super Keyword 🔗 open.substack.com/pub/gauravrs... #Java #JavaDeveloper #OOP #Programming #BackendDevelopment
super Keyword in Java
Access parent class members and simplify inheritance in Java.
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What's wrong with this code? Employee(String name) { name = name; } 🤔 The instance variable never gets initialized. ✅ Solution: this.name = name; Read my latest article on this keyword in java 🔗 open.substack.com/pub/gauravrs...? #Java #JavaDeveloper #OOP #Programming #ByteCraft
this.name
Can an Abstract Class have a constructor? 🤔 Most developers say "No." ✅ The correct answer is Yes. The constructor runs when a subclass object is created. Read my latest article on Abstract Class 🔗https://open.substack.com/pub/gauravrshegekar/p/abstract-class-in-java #Java #JavaDeveloper #OOP
Why does Java allow: ✅ Multiple Interfaces But not: ❌ Multiple Class Inheritance? Understanding this explains one of Java's biggest design decisions. Read my latest article on Interfaces 🔗 open.substack.com/pub/gauravrs... #Java #JavaDeveloper #SpringBoot #OOP #Programming #ByteCraft
Interface in Java
Define contracts that enable flexible and loosely coupled Java applications.
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What's the difference between: ✔️ Method Overloading ✔️ Method Overriding Read my latest article on Polymorphism 🔗 open.substack.com/pub/gauravrs...? #Java #JavaDeveloper #OOP #Programming #SpringBoot #ByteCraft
Polymorphism in Java
One method, many behaviors.
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Why doesn't Java support Multiple Inheritance using classes? 💡 Hint: It helps avoid the Diamond Problem. Read my latest article on Inheritance : 🔗 open.substack.com/pub/gauravrs...? #Java #JavaDeveloper #OOP #Programming #BackendDevelopment #ByteCraft
Inheritance in Java
Reuse existing code and build relationships between classes efficiently.
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What's the difference between Abstraction and Encapsulation? 👉 Abstraction hides implementation 👉 Encapsulation hides data. Read my latest article on Abstraction. 🔗 open.substack.com/pub/gauravrs... #Java #JavaDeveloper #OOP #Programming #SpringBoot #ByteCraft
Abstraction in Java
Hide implementation details and expose only the essential functionality.
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Is Encapsulation just making variables private and generating getters/setters? ❌ No. Encapsulation is about protecting object state through controlled access Read my latest article on Encapsulation, 🔗 open.substack.com/pub/gauravrs... #Java #JavaDeveloper #OOP #Programming #ByteCraft
Encapsulation in Java
Master one of the core principles of Object-Oriented Programming in Java.
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Can a constructor: ✅ Have parameters? ✅ Be overloaded? ❌ Have a return type? If you know the answers, you've already mastered one of Java's core OOP concepts. Read My latest article on Constructor: open.substack.com/pub/gauravrs...? #Java #JavaDeveloper #OOP #Programming
Constructors in Java
Learn how constructors initialize objects in Java
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