Just learned a tough lesson today!.Code that works locally doesn’t always work in production. Deployed a Spring Boot JAR & hit a ClassPathResource error while loading templates from resources. Reminder: test JARs like real prod!.#Java #SpringBoot #linux.

Need to take a step back. Feeling like I’m forgetting the DSA I’ve learned so far . Covered linear data structures but need more practice . For the next 1 week , I’ll revise all the concepts and patterns again . Sometimes, it feels like development is easier than DSA.

Today I got a DB error just because I used a primitive type in my entity. Primitives like int, boolean can’t be null, so JPA treats them like NOT NULL constraints automatically. Lesson learned: Always use wrapper classes in entities. They support null and avoid sneaky bugs.

Day 83 of Java Backend Journey .Had confusion between Association, Aggregation and composition cleared using hands on

Days 81 and 82 of Java Backend Journey .Spring Boot liquibase learning.→ pow(x) .→ permutation and combination .→ Letter Combinations of a Phone Number

Sometimes even small CRUD breaks in production. My code broke 3 times so far, and my lead could barely control his frustration — it was obvious. The code had more edge cases, and Each time it broke, I found a new edge cases. I hope it won’t break.

Sometimes Java libraries and their versions give a lot of trouble. I had to create a PDF using Thymeleaf, but faced CSS errors because iText doesn’t support advanced CSS. I wasted so much time on this. On top of that, IntelliJ is also not working properly on my PC these days.

Today I realized the importance of SOLID principles and design patterns. Working code doesn’t mean clean code. I’ve been fixing the messy logic I wrote earlier. It is been stressful and boring to modify and debug—AI couldn’t help either. Lesson learned! I Need to learn this thing

Faced a weird error while doing a data migration task using Liquibase .> Had to connect my local Spring Boot app to a PostgreSQL DB running on a Linux server. > Couldn’t connect because of a time zone mismatch. So I changed my Windows time to UTC — and it worked !

Internal Working (SSH Authentication Handshake)

I didn’t know about SSH when I first did this, but now as I’m learning networking, everything is starting to make sense!.

Spring Boot CI/CD with GitHub Actions .> Generated an SSH key pair .> Added the public key to the Linux server's authorized_keys file .> Stored the private key as a GitHub Secret . GitHub can connect to the server using SSH and deploy the app automatically

Day 80 of Java Backend Journey.Learning Networking Fundamentals .DSA : .→ Sqrt(x) .→ Climbing stairs .→ Tower of Honai .→ Josephus problem

React Query Learning.>No need to manually handle data, loading, or error states — React Query does it for you.> Cleaner code, focus on business logic.> caching — reuse data across components & auto-refetch when needed

> For the quiz restart feature, a backend call is sent if the user chooses an option or changes an option. While implementing this, I learned the concept of useRef.

Been working on my quiz platform frontend (React + Redux) for the past week.> Not confident with UI/UX & CSS, so used Cursor AI.> Used React Query for API data fetching (Spring Boot backend) instead of useState + useEffect.> Used Redux for global popups

Days 78 & 79 of Java Backend Journey .➤ Had a task to upload the daily database backup to S3.➤ SQL revision and practiced some easy LeetCode problems .DSA: .→ Remove Duplicates from a Sorted Array .→ Started Recursion.→ Solved basic problem and Rod Cutting Problem

Day 77 of Java Backend Journey .➤ Started Learning aws Lambda .➤ Difference between Object and ? in generic.➤ super vs extends in generics.DSA: .→ Daily Temperatures .→ Nearly sorted .→ Wiggle sort problem

Days 75 and 76 of Java Backend Journey .➤ Cloud Formation Practical by creating a simple EC2 instance and CloudTrail .DSA: .→ k Items with maximum sum .→ K largest sum .→ Task Scheduler: This problem helped to identify the use case of sorting and PriorityQueue

Day 74 of Java Backend Journey.➤ Virtualization and cloud formation of aws. DSA : .→ Time Needed to Buy Tickets