Interview Questions 21 total
Interview ×
0
1
answers
1What is the difference between a product company and a service company for developers?
**Service Company (IT Services / Outsourcing):**
TCS, Infosys, Wipro, HCL, Cognizant
- You work on clients' projects
- Technology stack deci...
0
1
answers
2How to answer 'Tell me about yourself' in a tech interview?
This is always the first question — most candidates waste it. Here's the formula:
**Structure: Present → Past → Future**
*Present:* ...
0
0
answers
3How does garbage collection work in Python?
Python uses two mechanisms for memory management:
**1. Reference Counting (primary):**
Every object has a reference count. When it reaches ...
0
0
answers
4What is the difference between multiprocessing and multithreading in Python?
Due to Python's GIL (Global Interpreter Lock), threads can't run Python code in parallel — only one thread executes at a time.
**Multithr...
0
0
answers
5How to prepare for a Java developer interview?
Java interviews at product companies cover 4 areas. Here's exactly what to prepare:
**1. Core Java (always asked):**
- OOPs: inheritance, p...
0
0
answers
6What is MongoDB aggregation pipeline?
The aggregation pipeline processes documents through a sequence of stages, similar to SQL's GROUP BY + JOINs.
**Common stages:**
- `` — f...
0
0
answers
7What is the difference between useCallback and useMemo in React?
Both are React hooks for performance optimisation — they prevent unnecessary recalculations:
**useMemo — memoises a VALUE:**
```jsx
con...
0
0
answers
8What is the difference between Git merge and Git rebase?
Both combine branches but in different ways:
**Git Merge:**
- Creates a new merge commit
- Preserves complete history with all branches vis...
0
0
answers
9What is multithreading in Java and how do you implement it?
Multithreading allows a Java program to execute multiple threads simultaneously, improving performance for concurrent tasks.
**Two ways to ...
0
0
answers
10What is the difference between ArrayList and LinkedList in Java?
Both implement the `List` interface but with different internal structures:
**ArrayList:**
- Backed by a dynamic array
- O(1) random access...
0
0
answers
11What is the difference between JDK, JRE, and JVM?
This is one of the most common Java interview questions.
**JVM (Java Virtual Machine):**
- Executes Java bytecode
- Platform-specific (Wind...
0
0
answers
12What certifications should I get to become an ethical hacker?
Here's the recommended certification path for ethical hacking:
**Beginner (Start here):**
- **CompTIA Security+** — foundational security...
0
0
answers
13How to pass the AWS Solutions Architect Associate exam?
The AWS SAA-C03 exam has 65 questions in 130 minutes. Here's the proven study plan:
**6-Week Plan:**
Week 1-2: Core services
- EC2 (instan...
0
0
answers
14How to prepare for a data science interview in 30 days?
**Week 1 — Statistics & Probability**
- Probability distributions, Bayes theorem
- Hypothesis testing, p-values
- A/B testing basics
**We...
0
0
answers
15Most common system design interview questions for software engineers
Top system design questions asked at product companies:
1. **Design a URL shortener** (Bit.ly)
2. **Design Twitter/Instagram** (social medi...
