Latest Questions 209 total
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136What 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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137What 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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138How 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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139What 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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140What 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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141How 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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142What 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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143What 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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144What 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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145What 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 ...
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146What 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...
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147What is Spring Boot and why is it used for backend development?
Spring Boot is a framework that makes it easy to create production-ready Java applications with minimal configuration.
**Why Spring Boot ov...
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148What 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...
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149What is the OWASP Top 10 and why does every developer need to know it?
OWASP Top 10 is the list of the 10 most critical web application security risks, updated every few years.
**2021 OWASP Top 10:**
1. Broken ...
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150What is a firewall and how does it work?
A firewall is a network security system that monitors and controls incoming/outgoing traffic based on predefined rules.
**Types of firewall...
