Technical Interview Questions
Frequently asked core subjects questions (OS, DBMS, Computer Networks, OOPs) and framework-specific queries.
1Object-Oriented Programming (OOPs)
Q: What are the 4 pillars of OOPs?
Encapsulation (hiding data), Abstraction (hiding implementation), Inheritance (code reuse), and Polymorphism (many forms/overloading).
Q: Difference between Interface and Abstract Class?
Abstract classes can have both implemented and abstract methods. Interfaces only have abstract methods (in Java pre-8). A class can implement multiple interfaces but inherit only one abstract class.
2Database Management Systems (DBMS)
Q: What are ACID properties?
Atomicity (all or nothing), Consistency (valid state), Isolation (concurrent execution is safe), Durability (committed data is saved).
Q: Difference between TRUNCATE and DELETE?
DELETE is DML (can be rolled back, slower). TRUNCATE is DDL (cannot be rolled back, faster, resets identity columns).
3Operating Systems (OS)
Q: What is a Deadlock?
A situation where a set of processes are blocked because each process is holding a resource and waiting for another resource acquired by some other process.
Q: Difference between Process and Thread?
A process is a program in execution (heavyweight, separate memory). A thread is a segment of a process (lightweight, shared memory).