Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. These 12 API concepts come up in almost every backend interview, and in every real system you will ever build. I recorded this after one of my Academy students got grilled on them, and I wanted to make it click for everyone. In this video I walk through how a client talks to a server, and everything that makes that conversation fast, safe, and reliable: HTTP methods, status codes, REST, auth, rate limiting, pagination, caching, versioning, idempotency, and webhooks. Whether you build with Java, Spring Boot, Node, Python, or any other stack, these are the fundamentals that separate juniors from engineers who actually understand APIs. ⏱️ Chapters 0:00 Intro 0:07 Client & Server (request and response) 0:54 HTTP Methods (GET, POST, PUT, PATCH, DELETE) 2:06 Status Codes (2xx, 3xx, 4xx, 5xx) 3:20 REST explained 4:09 Anatomy of a Request (headers, query params, body) 5:23 Authentication vs Authorization 6:54 Rate Limiting (429 and Retry-After) 7:50 Pagination (offset vs cursor) 8:59 Caching (cache hit, miss, and CDNs) 9:40 Versioning (v1, v2, deprecation) 10:40 Idempotency (idempotency keys, like Stripe) 11:30 Webhooks (stop polling, get pushed) 12:26 Recap and interview tips Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. Join my free community: https://skool.com/amigoscode Connect with me • LinkedIn: https://www.linkedin.com/in/nelsonamigoscode • Instagram: https://www.instagram.com/amigoscode • Twitter/X: https://x.com/amigoscode • GitHub: https://github.com/amigoscode #java #javadeveloper #springboot #softwareengineering

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. Deploying by hand is not careful. It is just slow and risky. CI/CD is not a tool you buy. It is a pipeline that builds, tests, and ships your code on every commit, so a human is never the thing standing between a change and production. Here is the mental model you should have → Continuous Integration builds and tests every push automatically → Problems surface in minutes, not on Friday at 5pm → A pipeline runs stages in order: build, then test, then deploy → Any failing stage stops the pipeline before bad code moves forward → Continuous Delivery ships passing changes to staging then production → The workflow lives as code in a yaml file next to your project → Rollback is one revert because every release is small and traceable The mistake juniors make is treating deploys as a manual ritual. They build on their laptop, copy files to a server by hand, and hope nothing breaks before the weekend. Senior engineers let a pipeline gate every change. They do not ask whether the build passed, they let the pipeline refuse to ship until it does. Green means it goes. Red means it stops. No guessing, no heroics. That is the real shift. You stop trusting attention and start trusting automation. If a teammate pushed a broken commit right now, would your pipeline catch it before it reached production, or would a customer catch it for you? Follow Amigoscode for practical lessons that help developers think like real software engineers #systemdesign #softwareengineering #devops #amigoscode #Shorts

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. Storing passwords in plain text is a critical security vulnerability. One data breach exposes every user's password. Use bcrypt, scrypt, or Argon2 to hash passwords with a unique salt per user. Never store, log, or display raw passwords. #database #sql #postgresql #amigoscode #Shorts

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. The hard part of caching is not the cache hit It is everything around the miss: who fills the cache, when it goes stale, and what happens when two requests miss at once Cache aside is the pattern that makes those answers explicit. The application, not the cache, owns the logic. Here is the mental model you should have → The application checks the cache first → On a hit it returns the cached value and skips the database → On a miss it reads from the database → It then writes that value back into the cache with a TTL → The next read for that key is now a fast hit → On a write it updates the database and invalidates the cached key The mistake developers make is trusting the cache blindly They cache with no expiry and serve stale data for hours They forget to invalidate on writes They let a hot key expire and send a stampede of misses straight at the database Senior engineers treat the cache as a copy, never the truth They set a TTL that matches how stale the data is allowed to be They invalidate on write so reads stay correct They protect the database from stampedes when a popular key expires A cache buys you speed by holding a copy, and every copy is a promise you have to keep in sync. If a cached value went stale today, would your users notice before your monitoring did Share your thoughts below Follow Amigoscode for lessons that turn developers into senior engineers #database #sql #postgresql #amigoscode #Shorts

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. Three traversals walk the exact same tree and return three completely different answers The shape of the tree never changes The only difference is when you visit the node Preorder visits the node before its children. Inorder visits the node between them. Postorder visits the node after both. Same recursion, one line moved Here is the mental model you should have → Depth first traversal is one recursive method, not three → Move the visit line before the children and you get preorder → Move it between the two recursive calls and you get inorder → Move it after the children and you get postorder → Inorder on a binary search tree returns values in sorted order → Preorder reads the root first, so it copies and serializes a tree → Postorder reads children first, so it deletes or evaluates from the bottom up → Every one of them is O of n, because each node is visited exactly once Juniors memorize the three orders and recite left, node, right on demand Seniors do not pick a traversal by name. They pick it by the output the problem needs Need sorted keys out of a search tree, reach for inorder. Need to clone or write the tree to disk, reach for preorder. Need to free children before parents or evaluate an expression tree, reach for postorder The traversal is not the goal. The order of the output is the goal, and the visit position is the only knob you turn If someone handed you a tree problem tomorrow, would you choose the order by habit or by the result you actually need Follow Amigoscode for practical lessons that help developers think like real software engineers #codingchallenge #datastructures #algorithms #amigoscode #Shorts

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. HashMap is NOT thread-safe. Concurrent access can cause infinite loops, lost updates, and corrupted data. Use ConcurrentHashMap instead if multiple threads need access. In interviews always mention that HashMap allows null keys but ConcurrentHashMap does not. #java #springboot #javadeveloper #amigoscode #Shorts

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. What actually happens to your bean between new and ready Most developers know Spring creates their objects. Far fewer know the stages in between. A Spring bean is not just constructed. It is instantiated, wired, post processed, and initialized before it is ever handed to you. Here is the mental model you should have → Component scan finds the classes that should become beans → Spring instantiates the bean, usually through its constructor → Dependencies are injected to populate its fields → Aware callbacks and BeanPostProcessors run before initialization → Init logic runs through afterPropertiesSet or an init method → The bean is now ready, and on shutdown its destroy logic runs The mistake developers make is doing real work in the constructor They touch injected dependencies before injection has happened They put startup logic in the constructor instead of an init callback They never learn why a proxy or a value was null too early Senior engineers respect the phases They keep constructors cheap and free of dependency use They put startup work in an init callback where dependencies exist They know a BeanPostProcessor is where the framework wraps their bean in a proxy The container is not magic. It is a defined lifecycle, and knowing the order tells you exactly when your code can safely run. If an injected dependency was null in your constructor today, would you know which phase had not run yet Share your experience below Follow Amigoscode for lessons that turn developers into senior engineers #java #springboot #javadeveloper #amigoscode #Shorts

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. Juniors scan a sorted array from the start. Seniors throw half of it away on the very first look. Binary search is not a trick you memorize. It is a way of thinking about a sorted space. The whole idea is simple. Every comparison should eliminate half the answers you still have left. If the array is sorted, one look at the middle tells you which half the target cannot be in, so you delete that half and repeat. Here is the mental model you should have → The array must already be sorted for any of this to work → Track two bounds, a low and a high, around the part you still trust → Compute mid as low plus high minus low over two to avoid overflow → Compare the value at mid to your target → Mid too small means the answer is to the right, so move low up → Mid too big means the answer is to the left, so move high down → Each step halves the remaining space, so the cost is order log n The mistake juniors make is reaching for a linear scan because it always works. It checks every element, one by one, and that is order n. On a sorted array that is wasted effort. Senior engineers see the sorted order as information they already paid for. They refuse to look at an element they can prove the target is not near. They guard the two bounds carefully because the bugs in binary search are almost never the idea, they are the off by one on low and high. That is the real lesson. The slow version looks at everything. The fast version looks at the middle and deletes a half it will never need to read. If your input was already sorted today, would your first instinct be to scan it, or to halve it? Follow Amigoscode for practical lessons that help developers think like real software engineers #codingchallenge #datastructures #algorithms #amigoscode #Shorts

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. Prints true. allMatch() checks if ALL elements satisfy the predicate. Every element (1, 2, 3) is 0. Also: anyMatch() for at least one and noneMatch() for zero matches. Short-circuits on first failure. #java #springboot #javadeveloper #amigoscode #Shorts

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. A JWT is not encrypted Anyone who intercepts it can decode it and read every claim inside What protects you is not secrecy. It is the signature. The token is signed, so the server can trust the claims were not tampered with, without storing a session anywhere. Here is the mental model you should have → The client logs in with credentials at the auth server → The auth server verifies them and returns a signed token → The client sends that token as a Bearer header on every request → The resource server verifies the signature using the public key → A valid signature means the claims inside can be trusted → No server side session is needed because the token carries the identity The mistake developers make is putting secrets in the payload They store sensitive data in claims anyone can read They forget to check the expiry They never plan for how to revoke a token that is still technically valid Senior engineers treat the token as a signed claim, not a vault They keep the payload minimal They keep expiry short They pair short lived access tokens with a refresh strategy they control Stateless auth is powerful, but only when you respect what the token actually is. If a token leaked today, would your system limit the damage or trust it until it expired Share your experience below Follow Amigoscode for lessons that turn developers into senior engineers #systemdesign #softwareengineering #devops #amigoscode #Shorts

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. A queue spreads wide. A stack dives deep. That single difference is the whole story of BFS versus DFS, and most people memorize the code without ever feeling why. Both walk the same graph. Both mark nodes as visited so they never loop forever. Both run in O of V plus E. What changes is the order, and the order is decided entirely by the data structure you reach for. Here is the mental model you should have → BFS uses a queue and visits every neighbor before going one level deeper → DFS uses a stack or plain recursion and goes as deep as it can before backtracking → BFS expands in rings outward from the start node → DFS plunges down one branch, hits a dead end, then climbs back up → BFS gives you the shortest path in an unweighted graph for free → DFS is the natural fit for cycles, full path exploration, and topological order → Both need a visited set, or they will revisit nodes and spin forever The mistake juniors make is picking a traversal at random and hoping it works They reach for whichever one they wrote last They get a path back, see it is valid, and move on But a valid path is not always the shortest path, and a graph with a cycle will hang a traversal that forgot its visited set Senior engineers choose by the problem, not by habit They ask whether the answer is about distance or about structure Shortest hops and levels means a queue Cycles, ordering, and exhaustive paths means a stack or recursion The algorithm is never the hard part once the question is clear If you were handed a graph problem tomorrow, would you know whether to spread wide or dive deep before you wrote a single line? Follow Amigoscode for practical lessons that help developers think like real software engineers #codingchallenge #datastructures #algorithms #amigoscode #Shorts

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. Most Java portfolios never get a reply. Here is the one project that changes that. If your GitHub is full of todo apps, weather apps, and CRUD clones, you are getting filtered out twice: first by the ATS robot scanning your resume for keywords, then by the hiring manager who closes the tab in six seconds. In this video I show you PayGuard, a production-grade backend project that beats both filters and gets Java developers interviews. PayGuard is a payment processing platform with AI-powered fraud detection. You build 5 microservices that handle real Stripe payments, talk to each other over Kafka, and score every transaction for fraud in real time using a machine learning model served in Java. It is the exact shape of what fintech and e-commerce companies run in production, which is why it turns into interview answers instead of just another repo. What you will learn: • Why todo apps and CRUD projects get your application rejected • How ATS keyword filtering kills resumes before a human ever reads them • The 4 things in PayGuard that make interviewers lean forward • Microservices and event-driven architecture with Kafka • Handling real payments with Stripe (charges, refunds, idempotent webhooks) • Serving a machine learning fraud model in Java with ONNX and a circuit-breaker fallback • Production engineering: Testcontainers, CI/CD, Docker, Kubernetes, monitoring Build PayGuard with the full spec, guided phases, and mentor code reviews inside Amigoscode Academy 👉 https://skool.com/amigoscode-academy Connect with me • LinkedIn: https://www.linkedin.com/in/nelsondjalo • Instagram: https://www.instagram.com/amigoscode • Twitter/X: https://x.com/amigoscode • GitHub: https://github.com/amigoscode #java #javadeveloper #springboot

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. A load balancer is not a router It is a bouncer that only sends traffic to the instances still standing Spreading requests across many instances is only half the job. Knowing which ones are healthy is the other half. Here is the mental model you should have → Clients send every request to the load balancer, not to an instance → The balancer distributes requests across a pool of instances → Round robin is the simplest policy, one instance after another → Health checks probe each instance to see if it is alive → An instance that fails its check is taken out of the rotation → When it recovers, the balancer adds it back The mistake developers make is assuming all instances are always up They balance traffic but never health check the targets They keep sending requests to an instance that is already dead They cannot explain why some requests fail and others do not Senior engineers treat health as part of routing They configure health checks that reflect real readiness They drain an instance before taking it down for a deploy They watch how traffic redistributes when one instance drops A load balancer is not just spreading load. It is continuously deciding which instances deserve traffic right now. If one instance went unhealthy today, would the balancer stop routing to it, or keep sending users into a wall Share your experience below Follow Amigoscode for lessons that turn developers into senior engineers #systemdesign #devops #docker #softwareengineering #amigoscode

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat.

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. 👉 Join our free community: https://skool.com/amigoscode Connect with me • LinkedIn: https://www.linkedin.com/in/nelsonamigoscode • Instagram: https://www.instagram.com/amigoscode • Twitter/X: https://x.com/amigoscode • GitHub: https://github.com/amigoscode #java #javadeveloper #springboot #claudecode #ai #softwareengineering #backenddevelopment

Become the software engineer AI can't replace. 😳 👉 Join Amigoscode Academy: https://skool.com/amigoscode-academy Members hired at Apple, Amazon & Just Eat. 👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy Spring Security is one of those topics most developers never fully understand - until now. In this updated 2026 crash course, I'll teach you everything you need to get up and running with Spring Security 7 (on Spring Boot 4 and Java 25). We cover the core architecture and the security filter chain, then implement real authentication step by step: Form Login, Basic Authentication, sessions & the JSESSIONID cookie, CSRF, the Authentication Manager & providers, custom UserDetailsService, and password encoding. By the end you'll understand how Spring Security actually works under the hood — and be able to confidently put it on your CV and demonstrate it in interviews. ⭐ Get the full course + diagrams + source code: https://skool.com/amigoscode 💬 Join the free community to ask questions & grab resources: https://skool.com/amigoscode 🧰 Requirements: • Java 25+ • Spring Boot 4 • Spring Security 7 📂 Source code & branches: https://github.com/amigoscode/spring-security ⏱️ *TIMESTAMPS* 00:00 Intro – what you'll learn 00:55 Spring Security architecture & the filter chain 07:14 Spring Security docs & versions (Spring Security 7) 10:49 Course repo & branches walkthrough 12:08 Requirements (Java 25, Spring Boot 4) & running the starter 16:42 Form Login – how it works (diagram) 20:38 Implementing Form Login (SecurityConfig) 27:38 Running the app & testing login 32:31 The JSESSIONID cookie explained 37:45 Storing sessions in Redis / JDBC 43:42 Customizing the login & logout 47:39 Exploring the filters in the source code 51:50 Basic Authentication – how it works (diagram) 56:10 Configuring Basic Auth (stateless + CSRF disabled) 1:01:54 Testing Basic Auth (browser, Base64, curl) 1:14:27 Realm name & WWW-Authenticate header 1:16:30 CSRF explained 1:18:45 Authentication Manager & Provider Manager 1:21:20 Debugging the DAO Authentication Provider 1:28:11 Custom users with UserDetailsService 1:36:11 Why login fails – the password encoder & NoOp 1:42:24 Password encoding & why we never store plain text 1:43:14 Wrap up 🔔 *Subscribe for more backend & security content!* https://www.youtube.com/@amigoscode?sub_confirmation=1 👉 *Land the job. Get the promotion. Become a better dev.* https://skool.com/amigoscode-academy 🤝 *Connect with me* • Skool: https://skool.com/amigoscode • LinkedIn: https://www.linkedin.com/in/nelsonamigoscode • Instagram: https://www.instagram.com/amigoscode • Twitter/X: https://x.com/amigoscode • GitHub: https://github.com/amigoscode #springSecurity #springboot #java

👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy 👉 Join my free community: https://skool.com/amigoscode Watch a real junior developer go through a full Java technical interview, with an AI playing the interviewer. If you have a Java interview coming up, this is exactly the kind of practice that gets you ready. TIMESTAMPS 00:00 Intro and getting to know the candidate 01:00 Object-oriented programming fundamentals 01:30 Encapsulation explained 02:20 Immutability and the String class 03:30 Java Collections Framework 04:30 ArrayList vs LinkedList 05:30 The Stream API 06:10 Candidate questions and wrap-up 07:20 Feedback and verdict Connect with me • LinkedIn: https://www.linkedin.com/in/nelsonamigoscode • Instagram: https://www.instagram.com/amigoscode • Twitter/X: https://x.com/amigoscode • GitHub: https://github.com/amigoscode 👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy 👉 Join my free community: https://skool.com/amigoscode #java #javadeveloper #springboot #claudecode #ai #softwareengineering #backenddevelopment

👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy 👉 Join my free community: https://skool.com/amigoscode/about Claude Code just shipped a brand new feature called Agent View — and it completely changes how you manage multiple AI coding sessions. No more juggling 10 terminal tabs trying to find which Claude session is doing what. In this video I show you exactly how to use it: pin sessions, rename them, run agents in the background with /bg, and even spin up 10 agents at once from a single screen. TIMESTAMPS 00:00 New Claude Code Agent View 00:50 How to launch /claude agents 01:30 Running multiple sessions at once 03:30 Navigating between agents (arrow keys + Alt+number) 04:40 Rename sessions (Ctrl+R) 05:25 Pinning sessions (Ctrl+T) 06:30 Sending a session to the background with /bg 08:20 Running 10 parallel agents from one prompt 09:30 Each session has its own context window 10:20 Keyboard shortcuts cheat sheet 👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy 👉 Join my free community: https://skool.com/amigoscode/about Connect with me • LinkedIn: https://www.linkedin.com/in/nelsonamigoscode • Instagram: https://www.instagram.com/amigoscode • Twitter/X: https://x.com/amigoscode • GitHub: https://github.com/amigoscode #claudecode #anthropic #ai

👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy 👉 Join the waitlist: https://skool.com/amigoscode-academy Spring Security 7 is finally here and we've rebuilt the course from the ground up. After years of breaking changes and outdated tutorials, this is the Spring Security course I've been wanting to make: a clean, modern, end-to-end roadmap that actually sticks. We're releasing it as a 3-part series: 🔐 Part 1 — Spring Security Foundations 🔑 Part 2 — JWT + Refresh Tokens 🚀 Part 3 — Advanced (coming soon) Parts 1 & 2 drop next week. Join the waitlist below to be the first in. What you will learn: ✅ Authentication vs Authorization (explained the way it should be) ✅ The Security Filter Chain — broken down piece by piece ✅ AuthenticationProvider, AuthenticationManager & SecurityContextHolder ✅ UserDetailsService & custom DAO authentication ✅ Form login, Basic Auth & sessions ✅ BCrypt, salting, hashing & why rainbow tables matter ✅ Roles vs Authorities (and why ROLE_ exists) ✅ Storing users, roles & permissions in a database ✅ JWT + Refresh Tokens from scratch ✅ Security Events with event listeners ✅ Common attacks & how Spring Security defends against them 👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy Join my free community: https://skool.com/amigoscode Connect with me • LinkedIn: https://www.linkedin.com/in/nelsonamigoscode • Instagram: https://www.instagram.com/amigoscode • Twitter/X: https://x.com/amigoscode • GitHub: https://github.com/amigoscode #java #springsecurity #jwt #springboot

👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy Most engineers take 7–10 years to reach Senior. Liana Ramazanova did it in 3. She's now a Senior Software Engineer at ABC Fitness — and in this live session she breaks down her exact playbook for accelerating to Senior in the AI era. WHAT YOU'LL LEARN → The decisions that compounded her growth early on → What she studied (and what she ignored) to accelerate → How she turned side projects into real career leverage → How she uses AI day-to-day to ship faster and learn deeper without becoming dependent on it → What AI actually means for junior engineers right now → The mistakes she'd avoid if she had to start over 👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy Connect with me • LinkedIn: https://www.linkedin.com/in/nelsonamigoscode • Instagram: https://www.instagram.com/amigoscode • Twitter/X: https://x.com/amigoscode • GitHub: https://github.com/amigoscode #java #javadeveloper #springboot #claudecode #ai #softwareengineering #backenddevelopment 🎙️ New to streaming or looking to level up? Check out StreamYard and get $10 discount! 😍 https://streamyard.com/pal/d/5167408537993216

👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy The complete Java Developer Roadmap for 2026 — everything you need to learn to stay relevant, land jobs, and build real production systems in the AI era. In this video I walk you through the full roadmap: from the must-have fundamentals (Linux, Git, terminal) all the way to AI agents, MCP, agentic coding, and deploying Java apps to the cloud. 🔥 Join my free community (roadmap diagram inside): skool.com/amigoscode Timestamps 00:00 Intro — Why 2026 is different 00:20 The Must-Haves: Linux, Git, Terminal, GitHub 02:22 Java Language Core: OOP, Functional, Modern Features 03:50 Platform & Tooling: JVM, Build Tools, IDEs 05:34 Testing: JUnit, Mockito, Testcontainers 05:58 Frameworks: Spring Boot & Friends 06:22 Databases: PostgreSQL, Redis, MongoDB 06:53 Messaging: Kafka, RabbitMQ, SQS 07:20 Architecture: Layered, DDD, Hexagonal 08:52 Microservices: Resilience, Service Discovery, API Gateway 10:03 Cloud Native: Docker, Kubernetes, Serverless 12:08 AI Foundations: LLMs, Context, Prompting 13:27 AI Agents, MCP & RAG 15:26 Agentic Coding: Claude Code, Codex, OpenCode 16:33 Cloud, CI/CD & Infrastructure as Code 17:27 DSA, System Design & AI Coding Interviews 18:47 Build Real Projects & Deploy to Production 19:22 LinkedIn, Networking & Standing Out 21:10 Wrap-Up What you'll learn • The exact tech stack Java devs need in 2026 • How AI (Claude Code, agents, MCP) is reshaping the workflow • Which frameworks, databases, and cloud tools actually matter • How to prep for modern Java interviews (LeetCode + AI coding rounds) • How to stand out in a tough job market Let me know in the comments — what's the number 1 area you're focusing on in 2026? 👉 Land the job. Get the promotion. Become a better dev. https://skool.com/amigoscode-academy Join my free community: https://skool.com/amigoscode Connect with me • LinkedIn: https://www.linkedin.com/in/nelsonamigoscode • Instagram: https://www.instagram.com/amigoscode • Twitter/X: https://x.com/amigoscode • GitHub: https://github.com/amigoscode #java #javadeveloper #springboot #claudecode #ai #softwareengineering #backenddevelopment

You're calling .equals() on a null reference. Boom — NullPointerException. The fix? Flip it: "John".equals(name). The constant can never be null so it safely returns false. This is called the Yoda condition and interviewers love asking about it.

== compares references, not values. Two 'new String()' calls create two different objects in heap memory. Always use .equals() for String comparison. This trips up even experienced devs in interviews. Quick fix: a.equals(b) returns true.

Prints true. Records can implement sealed interfaces. Circle is a permitted subtype of Shape. instanceof checks runtime type. Sealed types + records = powerful algebraic data types in modern Java.

If the app crashes between the two UPDATEs, $100 vanishes. The first debit commits but the credit never happens. This is why transactions exist — but the crash means no COMMIT or ROLLBACK. Make sure your app handles failures and the DB auto-rolls back uncommitted transactions. ACID matters.

Mutating a running total through a loop is harder to reason about. A stream with mapToInt computes each item independently and reduces. Immutable pipelines have fewer bugs.

localStorage is accessible to any JavaScript on the page — one XSS vulnerability exposes all tokens. Use httpOnly cookies instead: they can't be read by JavaScript. Add SameSite=Strict and Secure flags. Never store sensitive tokens in localStorage.

Streams express data transformations declaratively. Filter, map, collect. No mutable state, no manual list creation. The intent is clear: get names of active users.

Prints 2 then throws UnsupportedOperationException. Map.of() creates an IMMUTABLE map. put() is not allowed. Same for List.of() and Set.of(). Use new HashMap(Map.of(...)) if you need mutability.