Best collection of Java Interview resources including books, courses, interview questions and answers on different topics like core java, collections, mutlithreading, functional programming, serialization, design patterns and more.
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A comprehensive list of Java interview questions categorized by topic. These questions are asked multiple times on core Java interview to many developers, both junior developers with 1 to 2 years of experienced, intermediate developers of 3 to 5 years of experience and senior developers with 5 to 10 yeras of experience.
- Top 50 Java Programming Interview Questions
- 133+ Core Java Interview Questions for 2-5 Years Experienced Programmers
- 20 Core Java Interview Questions on Overloading and Overriding
- Top 50 Object-Oriented Programming (OOP) Concepts Interview Questions
- Top 20 Object-Oriented Programming (OOP) Concepts Interview Questions Answers
- Top 15 Java Method Overloading and Overriding Interview Questions
- What is Constructor Overloading in Java? Example
- Java Best Practices for Method Overloading? Examples
- Can You Overload or Override Static Methods in Java? Example
- What is Covariant Method Overriding in Java? Example
- Difference between Abstraction and Encapsulation in Java
- Difference between Abstract Class and Interface in Java
- Difference between Inheritance and Polymorphism in Java and OOP - Example
- Java Polymorphism Interview Questions and Answers
- 10 Object-Oriented Design Principles
- Java OOP Interview Questions and Answers
- Top 20 Java Interview Questions on Object-Oriented Programming
- Top 50 Collection Framework Interview Questions
- Top 50 Java Collection Framework Interview Questions
- Difference between ArrayList and HashSet in Java
- Difference between HashMap and HashSet in Java
- Difference between List and Set in Java
- Difference between HashMap and ConcurrentHashMap in Java
- Difference between ArrayList and LinkedList in Java
- Difference between HashMap and TreeMap in Java
- Top 15 ArrayList Interview Questions Answers in Java
- Difference between Hashtable and HashMap in Java
- Java HashMap Internal Implementation
- Difference between Iterator and Enumeration in Java
- Difference between ConcurrentHashMap and SynchronizedMap in Java
- Difference between Comparable and Comparator in Java
- What is NavigableMap in Java
- Top 30 Java Collection Framework Interview Questions
- Top 10 HashMap Interview Questions in Java
- Difference between Array and ArrayList in Java
- Difference between HashMap and LinkedHashMap in Java
- Top 10 ConcurrentHashMap Interview Questions in Java
- Difference between Vector and ArrayList in Java
- Difference between HashMap and WeakHashMap in Java
- Java Collections Framework Tutorial
- Difference between TreeSet and HashSet in Java
- How get() method of HashMap works in Java
- Java ArrayList contains() method example
- Difference between HashMap and IdentityHashMap in Java
- How to iterate over a HashMap in Java
- Difference between ArrayList and Vector in Java
- Top 10 Java Set Interview Questions
- Java Collections Framework Cheat Sheet
- Top 10 TreeMap Interview Questions in Java
- 50+ Java Multithreading and Concurrency Questions
- Top 30 Java Multithreading Interview Questions Answers
- Top 15 Java Multithreading Interview Questions
- Top 21 Java Multithreading Interview Questions with Answers
- Difference between Sleep and Wait in Java
- Difference between Notify and NotifyAll in Java
- Difference between Thread vs Runnable interface in Java
- Difference between synchronized and concurrent collection in Java
- What is the difference between process and thread in Java
- How to use Exchanger for inter-thread communication in Java
- What is Phaser in Java?
- What is a Daemon thread in Java and Difference with User thread
- How to use Fork Join in Java Multithreading
- Top 10 Java ConcurrentHashMap Interview Questions with Answers
- Top 50 Java Multithreading Interview Questions
- Java Concurrency and Multithreading Interview Questions
- Difference between Callable and Runnable in Java
- Difference between Synchronized Method and Synchronized Block in Java
- Difference between CyclicBarrier and CountDownLatch in Java
- What is ThreadLocal in Java
- Difference between Volatile and Atomic Variables in Java
- How to avoid deadlock in Java
- Difference between submit() and execute() method in Java
- How to Create a Thread-Safe Singleton in Java
- 20 Java 8 Interview Questions
- Top 50 Java 8 Interview Questions
- Top 15 Java 8 Stream and Functional Programming Interview Questions Answers
- Top 20 Design Pattern Interview Questions
- 20 Design Patterns for Java Interview Questions
- Top 10 Design Patterns Interview Questions in Java
- Difference between Factory and Abstract Factory Pattern in Java
- Top 10 Object-Oriented Design Principles and Patterns for Java Programmers
- What is Singleton design pattern in Java
- Observer Design Pattern in Java
- Difference between State and Strategy Design Pattern in Java
- How to implement Thread-Safe Singleton Pattern in Java
- How to impelment Builder Design Pattern in Java
- When to use Adapter Design Pattern in Java
- How Chain of Responsibility Design Pattern works in Java
- What is Decorator Design Pattern in Java
- What is Proxy Design Pattern in Java
- 10 Design Pattern Interview Questions and Answers
- Difference between Singleton and Static Class in Java
- Java Singleton Design Pattern Example
- Builder Design Pattern Example in Java
- Top 10 Design Patterns in Java
- Observer Design Pattern Example in Java
- Difference between Strategy and State Design Pattern in Java
- Decorator Design Pattern Example in Java
- Adapter Design Pattern Example in Java
- Difference between Adapter and Proxy Design Pattern in Java
- Facade Design Pattern Example in Java
- Chain of Responsibility Design Pattern Example in Java
- Factory Design Pattern Example in Java
- Abstract Factory Design Pattern Example in Java
- How to find the maximum occurring character in a given String
- How to remove a given character from a String
- How to count the occurrence of a given character in a String
- How to find all permutations of a given String
- How to reverse a given String in place
- How to check if two Strings are anagrams of each other
- How to convert a given String into an integer
- How to check if a given String is a palindrome
- How to find the first non-repeated character from a given String
- How to check if an array contains a number in Java?
- How to find all pairs in an array whose sum is equal to k
- How to remove duplicates from an array in Java
- Binary Search Algorithm without Recursion
- Prime Number Generation Algorithms - Sieve of Eratosthenes
- How to find largest and smallest number from integer array - Java Solution
- How to Reverse an Array in place in Java? Example Solution
- How to sort an Array in descending order in Java? Example Tutorial
- How to Rotate an Array to Left or Right in Java? Solution Example
- How to implement Bubble sort in Java?
- How to sort an array in place using the QuickSort algorithm?
- What is an array? Can you change the size of the array once created?
- Can you store String in an array of Integer in Java? compile-time error or runtime exception?
- What is the difference between ArrayIndexOutfOBounds and ArrayStoreException?
- Can you use Generics with an array?
- What is a two-dimensional array in Java?
- Do you have a three-dimensional array in Java?
- How to iterate over an array in Java?
- What is the difference between an array and a linked list?
- How to sort an array in Java?
- Top 21 Java Array Interview Questions and Answers
- What is the difference between an array and a linked list?
- How to implement a singly linked list in Java?
- How to reverse a singly linked list in Java?
- How to detect a loop in a linked list?
- How to find the middle element of a linked list in one pass?
- How to merge two sorted linked lists into one sorted linked list?
- How to delete a node from a singly linked list?
- How to find the nth node from the end in a singly linked list?
- How to sort a linked list in Java?
- What are the advantages and disadvantages of using a linked list over an array?
- How to detect and remove loop in a linked list in Java?
- How to find the intersection point of two linked lists?
- How to create a circular linked list in Java?
- Write a program to find all permutations of a given String?)
- Write a program to check if a given String is a palindrome()?
- Write a program to remove duplicates from an unsorted linked list?
- Write a program to find the length of a given linked list?
- Write a program to implement a quicksort algorithm using recursion?
- Write a method countLeaves() to find the total number of leaf nodes in a binary tree. If there are no leaf nodes, return 0
- Write a program to find the greatest common divisor or GCD of a given number?
- Write a program to convert a decimal number to a binary number?
- Write a program to print pre-order traversal of binary tree?
- Write a program to print in-order traversal of binary tree using recursion?
- Write a program to print post-order traversal of binary tree?
- Write a program to check if a given linked list is a palindrome?
- How to implement Merge Sort Algorithm in Java - Example Tutorial
- How to Find Nth Fibonacci Number in Java - Example Tutorial
- How to swap two Integers without using a temporary variable in Java?
- How to find Factorial in Java using Recursion and Iteration - Example Tutorial
- How to code Binary Search Algorithm using Recursion in Java? Example
- How to convert Decimal to Binary Number in Java? Example Tutorial
- Counting Sort in Java - Example
- How to check if an array contains a number in Java?
- How to sort an array in place using the QuickSort algorithm?
- How do you print all duplicate elements from the array in Java?
- Top 100 Data Structure and Algorithm Interview Questions for Java Programmers
- Top 30 Stack and Queue Data Structure Interview Questions for Practice
- Top 40 Binary Tree Coding Interview Questions for Programmers
- Top 22 Array Concepts Interview Questions Answers in Java
- 75+ Coding Interview Questions for Programmers
- 50+ Data Structure and Algorithms Problems from Interviews
- Top 50 Array Coding Problems for Interviews
- Top 20 Linked List Interview Questions for Programmers
- Top 10 Algorithm Interview Questions for Programmers
- Top 50 Core Java Interview Questions Answers
- Top 30 Core Java Interview Questions for 2 to 3 years Experienced Programmers
- Top 50 Java Collections Interview Questions
- Top 20 Java Thread Interview Questions Answers
- Top 40 Java Programming and Coding Interview Questions
- Top 10 Java Multithreading Interview Questions Answers
- Top 10 Java Serialization Interview Questions and Answers
- Top 10 Java Exception Handling Interview Questions Answers
- Top 15 Java NIO Interview Questions Answers
- Top 10 JDBC Interview Questions Answers for Java Programmers
- Top 10 Java Concurrency Interview Questions and Answers
- 50 Java Coding Interview Questions for Programmers
- 20 Core Java Interview Questions from Investment Banks
- 10 OOP Design Principles Java Programmer should know
- 20 Java Collections and Generics Interview Questions
- 15 Serialization Interview Questions in Java
- 10 Exception Handling Interview Questions in Java
- 10 Concurrency and Multithreading Interview Questions
- 10 JDBC Interview Questions for Java Programmers
- Top 10 Java Concurrency Interview Questions
- Top 10 Core Java Interview Questions for Beginners
- Top 10 Java String Interview Questions