francis mwangi

Software engineer( MERN Stack, Java, Spring MVC, Spring Boot).

[francis mwangi @frammwas]

@Cedric_SNR @NytoP2PMwangi That is send money response payload, for till and pay bill the details are masked.

[francis mwangi @frammwas]

@BRIGHTZEED Kaende Sana!

[SumitM @SumitM_X]

API concepts that are discussed in interviews , don't skip these if you are a backend dev :

1. Idempotency: Know why PUT/DELETE are idempotent but POST isn’t. Helps avoid accidental double writes.

2. Pagination: Offset works until scale hits. Cursor/keyset is what you need for big data sets.

3. Versioning: URI vs Header vs Query param. There’s no one right way, just tradeoffs.

4. Rate limiting: Token bucket > naive fixed window if you care about fairness.

5. Error contracts: 400 (bad request) ≠ 422 (validation issue) ≠ 409 (conflict). Don’t just throw 500 everywhere.

6. Caching: ETag + Cache-Control save you from unnecessary DB load.

7. Security: JWTs expire for a reason. Don’t stuff user PII inside them.

8. N+1 Queries: Kill them early. Use batching or joins when returning nested resources.

9. Docs: OpenAPI/Swagger is not optional.

10. Consistency: Sometimes cached data is good enough.

[SumitM @SumitM_X]

1. Agreed, microservices aren't always the answer. But in complex, distributed orgs or teams with independently deployable units, they still solve real-world scale and autonomy issues when used with care.
2. IPC/shared memory & domain sockets : valid, especially for services colocated on the same node. In practice though, many teams trade off raw performance for cloud-native flexibility and deployment agility.
3. Presigned URLs & large packets : yes Leveraging these can drastically reduce load on internal services.

[SumitM @SumitM_X]

Common Java interview questions for beginners :

- Why Strings are immutable?
- Write your own immutable class
- shallow vs deep cloning
- How Can we write custom exception?
- Producer/Consumer problem using wait and notify
- noclasdeffound vs classnotfound
exception

[SumitM @SumitM_X]

Java multithreading interview questions for beginners -

- difference between synchronized blocks and the volatile keyword.
- Explain the concept of reentrant locks in Java
- difference between Thread.sleep() and Object.wait() methods
- What is a thread-local variable in Java?

[Tech Fusionist @techyoutbe]

AWS Learning (Day 1 to Day 4) 🔥🔥

Day 1 – What is AWS
https://t.co/CBcoqpkqdq

Day 2 – Core AWS Services
https://t.co/u0Wo4LvC6q

Day 3 – AWS Console Tour
https://t.co/Nrns7Z5qjm

Day 4 – S3 Basics
https://t.co/blqEBZIjWc

Day 5 – EC2 Basics (Coming tomorrow)

Check & Share to support!! 🔥🔥

[Skilled Coder @theskilledcoder]

Behind the Scenes of Every Web Request

[Skilled Coder @theskilledcoder]

Cloud Concepts Every Developer Should Know

[Skilled Coder @theskilledcoder]

Simple Explanation of How Docker Works

[SumitM @SumitM_X]

Below are Top 7 skills required for Java devs to get a job these days.

Which one are you struggling with ?
What’s your Achille's heel ?

1. Core Java (8–21) – Streams, records, virtual threads, collections, OOP

2. Spring Boot: REST APIs, validation, profiles, AOP, actuator, config management, devtools, custom starters, error handling.

3. Microservices: Feign/WebClient, API versioning, service discovery, config server, circuit breakers, retries, distributed tracing, API Gateway,SAGA, CQRS.

4. Spring Security – JWT, OAuth2, role-based auth

5. Hibernate/JPA – Mappings, lazy/eager, JPQL, performance tuning

6. DSA – Arrays, trees, graphs, DP, hashing

7. Concurrency – Thread pools, locks, CompletableFuture, Loom

[francis mwangi @frammwas]

@UndercoverKe @C_NyaKundiH If an AI-powered spacecraft can land on a moving asteroid, drill a hole, collect samples, send them back to Earth, and continue to other missions, what can’t AI do? All of the above are effortless for AI-powered robots.

[francis mwangi @frammwas]

Even a dog can do sales let alone AI.

[Othul Mamba @OthulMamba]

@Kenyanimimi @C_NyaKundiH It won't take sales roles.

[React @reactjs]

React 19.1 has just been released! Check out the latest updates here: https://t.co/3SY0SABy48

[Mohit Mishra @chessMan786]

Coding your own database server in C
In this series you will learn how to design data structures and how to think when designing and coding a fast in-memory database server. You will learn about Tcp network connections and parsing of Cli commands

[Stanislav Kozlovski @kozlovski]

Apache Kafka 4.0 was just released!

It bumps Kafka to 1.4 million lines of code.

What comes with this new release?

Here are the top 3 features you should know about 🔥

[SumitM @SumitM_X]

As a backend developer , expect some database questions as well in interviews.

Some common questions are :

- Difference between clustered and unclustered indexes
- what are materialized views
- Difference between procedure and functions
- Find employee with nth highest salary

[SumitM @SumitM_X]

As a Java developer, caching and performance are common interview topics. Make sure to read about these 20 key caching concepts before your interview 👇

1. Fundamentals of Caching: Types (In-Memory, Distributed, Persistent), Eviction Policies (LRU, LFU, FIFO, ARC)

2. Cache Invalidation Strategies: Write-Through, Write-Behind, Lazy Loading, TTL

3. Spring Boot Caching Basics (@ Cacheable, @ CachePut, @ CacheEvict) and Providers (Redis, Ehcache, Caffeine, Hazelcast)

4. Hibernate Caching Overview: First-Level vs. Second-Level Cache, Query Cache, and Their Use Cases

5. Handling Stale Data in Hibernate Cache Due to External DB Updates and Using Event Listeners for Cache Eviction

6. Redis Caching Basics: Key-Value Storage, Persistence (RDB, AOF), Expiry Policies

7. Redis Advanced Data Structures for Caching: Strings, Hashes, Lists, Sets, Sorted Sets

8. Redis Transactions and Pipelining: Optimizing Cache Writes

9. Redis Pub/Sub: Real-Time Messaging for Cache Invalidation Across Applications

10. Redis Cluster and Replication: Ensuring High Availability and Scalability

11. Redis Eviction Policies: LRU, LFU, Random, Noeviction Strategies

12. Redis LUA Scripting: Optimizing Batch Cache Operations

13. Redis Performance Optimization: Connection Pooling, Thread Tuning, Memory Optimization

14. Memcached vs. Redis: Key Differences and When to Use Each

15. Hazelcast and Apache Ignite: Distributed Caching, Near Cache, and In-Memory Data Grid Features

16. Cache Synchronization Across Microservices: Challenges and Solutions Using Redis

17. Implementing Cache Refresh Jobs to Handle Stale Data Automatically

18. Best Practices for Distributed Caching in Java: Avoiding Cache Stampede, Thundering Herd Problem

19. Optimizing Cache TTL: Balancing Performance and Data Freshness in Redis and Other Caches

20. Monitoring and Debugging Caches: Redis Insight, Micrometer, Prometheus, and Grafana

[Elon Musk @elonmusk]

Time to go to Mars
https://t.co/qwuqbvqBOL

[Ashish Pratap Singh @ashishps_1]

30 Blogs to Learn 30 System Design Concepts:

1. APIs: https://t.co/SFR7c1yi1Z

2. API Gateway: https://t.co/kjlIJy9ElI

3. Scalability: https://t.co/Gbpjax24gd

4. Availability: https://t.co/GfakejdGQz

5. CAP Theorem: https://t.co/Aaq5s96WFU

6. Load Balancers: https://t.co/O4WkWoVCuC

7. Load Balancing Algorithms: https://t.co/zrVmh7rURa

8. Caching: https://t.co/Jed9uIFFim

9. Caching Strategies: https://t.co/xhxmMgVQvW

10. Cache Eviction Strategies: https://t.co/eGUV3zzG3A

11. Distributed Caching: https://t.co/W8eX81OAKp

12. CDNs: https://t.co/kPyu251AjO

13. Database Types: https://t.co/zhPaltn2bo

14. SQL vs NoSQL: https://t.co/vDTE5PqNel

15. ACID Transactions: https://t.co/eQBBIIM6w9

16. Database Indexes: https://t.co/CKk39deBkk

17. Database Sharding: https://t.co/nIkBZ8FZtv

18. Database Scaling: https://t.co/vZ7rdPddoC

19. WebSockets: https://t.co/IhWwUY8wku

20. Message Queues: https://t.co/BTX85efXZu

21. Service Discovery: https://t.co/JK8uJkgSQf

22. Bloom Filters: https://t.co/vNV9yFrixf

23. Rate Limiting Algorithms: https://t.co/mjnf3S9PUA

24. SPOF: https://t.co/5FtrH1Shrc

25. Idempotency: https://t.co/lsMSkZrS38

26. Checksums: https://t.co/lFq0K6Cy6z

27. Long Polling vs WebSockets: https://t.co/MB628lZb2w

28. Concurrency vs Parallelism: https://t.co/DWmMDNjkxR

29. Proxy vs Reverse Proxy: https://t.co/AR8L9F2met

30. Batch vs Stream Processing: https://t.co/q3MCCs26wd

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