Technical interviews scare most freshers — but they test the same core topics every time. Here are the most common technical interview questions for freshers, with concise answers.
Data Structures & Algorithms
1. What is the difference between an array and a linked list? An array stores elements in contiguous memory with O(1) access by index but costly insertions. A linked list stores nodes with pointers — O(1) insertion/deletion but O(n) access.
2. Explain time complexity / Big-O. It describes how an algorithm's running time grows with input size — e.g., O(1) constant, O(n) linear, O(n²) quadratic, O(log n) logarithmic.
3. What is a stack vs a queue? A stack is LIFO (last-in-first-out); a queue is FIFO (first-in-first-out).
OOP
4. What are the four pillars of OOP? Encapsulation, Abstraction, Inheritance and Polymorphism.
5. Difference between overloading and overriding? Overloading = same method name, different parameters (compile-time). Overriding = subclass redefines a parent method (run-time).
Databases
6. What is a primary key vs a foreign key? A primary key uniquely identifies a row; a foreign key references a primary key in another table to link data.
7. What is normalization? Organizing tables to reduce redundancy and improve integrity (1NF, 2NF, 3NF).
8. INNER JOIN vs LEFT JOIN? INNER JOIN returns matching rows in both tables; LEFT JOIN returns all rows from the left table plus matches from the right.
Web / General
9. What happens when you type a URL and press Enter? DNS resolves the domain to an IP, a TCP/HTTPS connection is made, the server returns HTML/CSS/JS, and the browser renders the page.
10. What is a REST API? A stateless way for systems to communicate over HTTP using methods (GET, POST, PUT, DELETE) and JSON.
How to Answer
- Think out loud — interviewers assess your approach, not just the answer
- If stuck, state your assumptions and start with a brute-force solution
- Always relate answers to your projects when possible
Practice more with our free interview question bank. Language-specific? See Java interview questions for freshers. Then create a free profile and apply to software developer fresher jobs.