Latest Questions 214 total
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136How 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 ...
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137What are Python generators and when should you use them?
A generator is a function that yields values one at a time instead of returning them all at once — saving memory.
**Regular function vs G...
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138What 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...
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139How 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...
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140What skills are needed to become a DevOps engineer in 2025?
DevOps engineer is one of the highest-paying roles in tech. Here's the complete skill map:
**Foundation (must-have):**
- Linux command line...
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141What is the salary of a full stack developer in India 2025?
Full stack developer salaries in India (2025):
**By experience:**
- Fresher (0-1 year): ₹3.5 – ₹7 LPA
- Junior (1-3 years): ₹7 – ...
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142What is MongoDB aggregation pipeline?
The aggregation pipeline processes documents through a sequence of stages, similar to SQL's GROUP BY + JOINs.
**Common stages:**
- `` — f...
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143How do you handle authentication in a MERN stack app?
The standard approach uses JWT (JSON Web Tokens):
**Flow:**
1. User logs in → sends email + password to Express
2. Express validates cred...
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144What 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...
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145What is the MERN stack and how does it work together?
MERN is a full-stack JavaScript framework combining 4 technologies:
**M — MongoDB:** NoSQL database (stores data as JSON documents)
**E �...
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146How does Docker networking work?
Docker networking allows containers to communicate with each other and the outside world.
**Default network types:**
1. **bridge** (defaul...
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147What 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...
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148What is Kubernetes and why is it used?
Kubernetes (K8s) is an open-source container orchestration platform that automates deployment, scaling, and management of containerised appl...
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149What is CI/CD and how does it work?
CI/CD stands for Continuous Integration and Continuous Delivery/Deployment.
**Continuous Integration (CI):**
- Developers push code frequen...
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150What 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 ...
