Mock Interview
Selection depends on how you present your knowledge, not just on knowing it. Reading is half the preparation; practising out loud is the real preparation. This page has 3 layers: HR answers, technical viva and a project deep-dive.
Layer 1
Don't memorise answers. Remember the framework and fill it with your own real story.
Present - Past - Future (60-90 seconds)
Avoid: Reading your resume line by line, starting with family details, or talking for 3 minutes.
2 skills from the JD + 2 proof points of yours
Avoid: An answer without proof, like 'Because I am hardworking'.
Strength + example; Weakness + improvement step
Avoid: 'My weakness is that I am a perfectionist.' It sounds rehearsed.
Growth + company alignment
Avoid: Answers like 'I'll do an MBA' or 'I'll start my own company' that suggest you will leave soon.
Honest answer + flexibility
Avoid: Saying 'Yes' in the interview and refusing at joining. That breaks trust.
STAR: Situation, Task, Action, Result
Avoid: A story where the problem was someone else's fault and you did nothing.
1-2 prepared questions
Avoid: Saying 'No questions', or asking about salary and leave first.
Layer 2
These 4 subjects appear in almost every technical interview. Read the topics, answer each question out loud, then compare with the hint.
| Subject | Topics to master |
|---|---|
| OOPs | 4 Pillars, Class vs Object, Abstract class vs Interface, Overloading vs Overriding, Constructors, Access modifiers |
| DBMS and SQL | Normalisation (1NF, 2NF, 3NF, BCNF), Joins, ACID properties, Keys, Indexing, Common SQL queries |
| Operating System | Process vs Thread, Deadlock, CPU Scheduling, Paging, Virtual Memory, Mutex vs Semaphore |
| Computer Networks | OSI Model, TCP vs UDP, IP vs MAC address, DNS, HTTP vs HTTPS, What happens when you type a URL |
Encapsulation, Abstraction, Inheritance, Polymorphism. Keep one real-life example ready for each.
An abstract class can hold state and concrete methods; an interface is a contract. In Java a class can extend one abstract class but implement many interfaces.
Overloading: same name, different parameters, resolved at compile time. Overriding: a child class redefines a parent method, resolved at runtime.
A special method that runs when an object is created. Yes, it can be private, as in the Singleton pattern.
The diamond problem: if two parents have the same method, it is ambiguous. Interfaces handle this.
Splitting tables to reduce redundancy and anomalies. 1NF: atomic values, 2NF: no partial dependency, 3NF: no transitive dependency.
Atomicity (all or nothing), Consistency, Isolation (transactions don't interfere), Durability (data is safe after commit).
INNER: only matching rows. LEFT: all rows from the left table, with NULL where the right side has no match.
DELETE removes rows, supports WHERE and can be rolled back. TRUNCATE removes all rows quickly. DROP removes the whole table and its structure.
SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(salary) FROM employees);
A primary key uniquely identifies a row (no NULLs). A foreign key refers to the primary key of another table.
A process has its own memory space; threads share the memory of one process, so they are lighter and switch faster.
Processes wait forever for each other's resources. Conditions: Mutual Exclusion, Hold and Wait, No Preemption, Circular Wait.
Mutex: one owner at a time, and the owner unlocks it. Semaphore: counter-based, can manage multiple resources.
Dividing memory into fixed-size pages/frames to avoid external fragmentation.
Using part of the disk as if it were RAM so a program can be larger than physical memory. A page fault loads the page.
Physical, Data Link, Network, Transport, Session, Presentation, Application. Mnemonic: 'Please Do Not Throw Sausage Pizza Away'.
TCP: connection-oriented, reliable, ordered (web, email). UDP: connectionless, fast, no guarantees (video calls, gaming, DNS).
IP is a logical address that can change between networks (Network layer). MAC is a hardware address (Data Link layer).
It translates a domain name (placementsaathi.in) into an IP address.
DNS lookup -> TCP connection (plus a TLS handshake for HTTPS) -> HTTP request -> server response -> the browser renders the page.
Layer 3
For every word on your resume, be ready for at least 3 follow-up questions. Know the 'why' behind every technical decision.
Problem: what you solved
Solution: what you built and with which tech
Result: what changed (real numbers)
Learning: what you learned and would do differently
Don't wait for someone to mock-interview you. Your phone is enough.
Turn on your phone camera and answer one HR or technical question as you would in the interview.
HR answers in 60-90 seconds, technical concepts in 1-2 minutes. Use a timer to see where you over-talk.
Review the recording: filler words, eye contact, clarity. Write down one thing to improve next time.
Polish just one answer per day. In 30 days you will have 30 polished answers.
Your next step
Every company has different rounds and focus areas. Before a test, revise only that company's page.