List of Java fresher interview questions and potential coding round programs/topics often covered in interviews:

Here’s a list of Java fresher interview questions and potential coding round programs/topics often covered in interviews:

Common Java Fresher Interview Questions

Core Java

1. OOP Concepts:

- What are the pillars of Object-Oriented Programming?

- Explain the difference between abstraction and encapsulation.

- What is polymorphism? Explain with examples.

2. Java Basics:

- What is the difference between JDK, JRE, and JVM?

- Explain the public static void main(String[] args) method.

- What are constructors, and how are they different from methods?

- What are access modifiers in Java?

3. Collections Framework:

- What is the difference between ArrayList and LinkedList?

- How is HashMap different from Hashtable?

- Explain Set, List, and Map interfaces.

4. Multithreading:

- What is the difference between Runnable and Thread?

- Explain synchronization in Java.

- What are volatile and transient keywords?

5. Exception Handling:

- What is the difference between checked and unchecked exceptions?

- How does try-catch-finally work?

- Explain the throw vs throws keywords.

6. Java 8 Features:

- What are functional interfaces?

- Explain Stream API and its use.

- What are Optional and Lambda expressions?

7. Miscellaneous:

- What is the difference between == and .equals()?

- How does garbage collection work in Java?

- Explain the final, finally, and finalize keywords.

Coding Round Programs

Basic Level

1. Write a program to reverse a string.

2. Find if a number is prime.

3. Print Fibonacci series up to a given number.

4. Find the factorial of a number.

5. Check if a string is a palindrome.

Intermediate Level

1. Find duplicates in an array.

2. Sort an array using bubble/selection/insertion sort.

3. Implement a program to find the second largest number in an array.

4. Check for balanced parentheses in an expression.

5. Find the missing number in an array of size n containing numbers from 1 to n+1.

Advanced Level

1. Implement a custom LinkedList or Stack class.

2. Write a program to perform binary search.

3. Find the longest substring without repeating characters.

4. Detect a cycle in a linked list.

5. Implement LRU Cache using a data structure like HashMap and LinkedList.

Tips for Preparation

- Focus on understanding data structures like arrays, lists, stacks, queues, and trees.

- Practice basic algorithms such as searching, sorting, and recursion.

- Familiarize yourself with String manipulation methods in Java.

- Be clear about time complexity and space optimization.

- Work on a few real-world projects to understand the application of Java concepts.