Blog of Vincent VAUBAN

🧭☕ ASK VINCENT: HOW TO GROW AS A JAVA ENGINEER FOR INTERNATIONAL MARKETS

Mon, 25 May 2026 16:58:09 -0700

A Java backend/full-stack developer recently asked me a very good question:

“How can I improve technically and become strong enough to work remotely or internationally for the European or U.S. market?”

Here is my honest answer. 👇

🔸 TL;DR

▪️ Master Java + Spring Boot, but don’t ignore Jakarta EE.

▪️ Then expand toward frontend, cloud-native, Kafka, Kubernetes, and AI-assisted engineering.

▪️ A strong developer writes code. A remarkable engineer also shares, communicates, teaches, mentors, and builds trust.

▪️ For Europe or the U.S., English, visibility, network, and consistency matter a lot.

🔸 1. FOCUS FIRST ON A SOLID JAVA BACKEND FOUNDATION

As I position myself as an Oracle ACE and vExpert, my advice is simple:

▪️ Go deep on Java ☕

▪️ Become very comfortable with Spring Boot 🌱

▪️ Also learn Jakarta EE, because it is still very relevant in enterprise environments 🏢

Once this first step is reached at a good enough level, choose your expansion path:

▪️ Either go toward frontend: React, Vite, Angular, TypeScript

▪️ Or go toward platform/backend depth: Kubernetes, Kafka, cloud-native architecture

And all along this path, get acquainted with AI.

Not to replace your skills.

But to amplify them.

The direction I like to call it is:

Java Fullstack = Back + Front + Ops + Stream + AI-assisted engineering

🔸 2. WHAT SEPARATES A GOOD JAVA DEVELOPER FROM A WORLD-CLASS ENGINEER?

A good Java developer can deliver value in their daily role.

But a developer who...Read More

🖥️🌱 SPRING SHELL: WHEN YOUR SPRING BOOT APP NEEDS A TERMINAL

Mon, 25 May 2026 16:52:36 -0700

🔸 TL;DR

Spring Shell lets you build interactive CLI / REPL applications with the Spring programming model.

Not every internal tool needs a REST API. Not every admin task needs a web UI. Sometimes, a clean terminal command is enough. ⚡

Spring Shell gives you:

▪️ Commands

▪️ Arguments and options

▪️ Tab completion

▪️ Help output

▪️ Input reading

▪️ Spring beans, DI, config, validation

▪️ Interactive and non-interactive execution

Basically: Spring Boot, but for terminal-first tools.

https://docs.spring.io/spring-shell/reference/index.html

🔸 1. CREATE A SIMPLE COMMAND

Run it:

This is the Spring Shell sweet spot: expose business or operational logic as a simple command instead of creating a web endpoint just to trigger it.

🔸 2. GROUP COMMANDS LIKE A REAL CLI

Run it:

This makes your CLI discoverable.

Instead of a flat list of random commands, you can organize features around business domains:

▪️ user create

▪️ user disable

▪️ batch run

▪️ report export

▪️ cache clear

Very close to how developers already think with tools like git, kubectl, or docker. 🧠

🔸 3. ASK FOR INPUT INSIDE A COMMAND

This is useful when a command needs an interactive flow:

▪️ ask for a value

▪️ hide a password

Eventual consistency means your distributed system may be temporarily out of sync… but it is designed to converge toward a coherent state. ✅

In modern Java applications, this often happens when you use events, queues, projections, caches, or read models.

The trap? Thinking “not immediately consistent” means “broken.” Sometimes, it just means “asynchronous by design.” ⚙️

🔸 WHAT DOES EVENTUAL CONSISTENCY MEAN?

In a monolith, you often expect this:

Everything happens in one flow.

But in distributed systems, we often do this instead:

Then other parts of the system react later:

The system is temporarily incomplete.

But after all events are processed, the global state becomes coherent again. 🔄

🔸 EXAMPLE 1: THE ORDER IS CREATED FIRST

The order exists immediately. But the invoice, stock reservation, email notification, or analytics update may arrive later.

That is not necessarily a bug. That is an architectural choice.

🔸 EXAMPLE 2: THE READ MODEL IS UPDATED LATER@Componen

Your write model may already know the order exists. Your read model may not know it yet.

For a short time, the UI might say:

That can be acceptable… if the user experience explains it properly.

🔸 EXAMPLE 3: MAKE EVENT HANDLING IDEMPOTENT

With eventual consistency,...Read More

🧩⚙️ FLOWLOGIX EE COMPONENTS: JAKARTA EE HELPERS THAT REMOVE BORING BOILERPLATE

Mon, 25 May 2026 16:38:35 -0700

🔸 TL;DR

FlowLogix EE Components is not “yet another framework”.

It is a small utility layer for Jakarta EE apps that helps with:

▪️ PrimeFaces lazy DataTables

▪️ JPA finder logic

▪️ CDI-friendly plumbing

▪️ Less repetitive enterprise code

Basically: less ceremony, more useful code. 😄

https://github.com/flowlogix/flowlogix

🔸 1. JPA FINDER WITHOUT A GIANT BASE DAO

You get reusable JPA finder behavior without forcing every DAO to extend a massive abstract class.

That is very Jakarta EE-friendly:

▪️ composition

▪️ CDI injection

▪️ less inheritance magic

▪️ cleaner DAOs

Simple. Useful. Boring in the best possible way. ✅

🔸 2. COMPOSABLE QUERY LOGIC

This is where FlowLogix starts to feel practical.

Instead of scattering query logic everywhere, you can compose it.

The value is not “wow syntax”.

The value is:

▪️ reusable filters

▪️ cleaner query code

▪️ less DAO duplication

▪️ easier maintenance

For enterprise apps, this matters. A lot.

🔸 3. PRIMEFACES LAZY DATATABLE WITH LESS PAIN

And in the JSF page:

PrimeFaces lazy tables are powerful.

But wiring pagination, sorting and filtering manually can quickly become painful.

FlowLogix gives you a cleaner integration...Read More

🧩🗄️ how do you fetch a multi-level object graph? JOIN/ MULTISET/ SPLIT/ DEPENDS

Mon, 25 May 2026 15:42:02 -0700

Let’s say you have this kind of model:

Post -> Comments -> Votes -> Tags

And now you need to fetch it efficiently.

What would you choose? 👇

Poll options:

1️⃣ One giant JOIN fetch 🧨

2️⃣ jOOQ MULTISET DTO 🧩

3️⃣ Split JPA queries 🎯

4️⃣ It depends 🤷‍♂️

🔸 WHAT EACH OPTION MEANS

▪️ One giant JOIN fetch 🧨

Everything in one query: posts, comments, votes, tags.

It looks attractive, but it can create a Cartesian product:

posts × comments × votes × tags.

▪️ jOOQ MULTISET DTO 🧩

Instead of flattening everything into duplicated rows, you shape the result as nested DTOs.

Very interesting for read models and API responses.

▪️ Split JPA queries 🎯

Fetch the root first, then fetch one collection at a time.

Less magical, but often more predictable with Hibernate/JPA.

▪️ It depends 🤷‍♂️

Because the right answer depends on the use case: detail page, paginated list, read-only API, collection size, caching, and performance constraints.

As Martin Fowler said:

“Any fool can write code that a computer can understand....Read More

🚀☕ JAVA 26 & 27: WHAT DEVELOPERS SHOULD REALLY WATCH

Mon, 25 May 2026 15:39:57 -0700

Java 26 and Java 27 are not just “another JDK release cycle”.

They bring a mix of features that impact how we write code, how we run applications, and how we think about long-term platform security.

Some features are directly visible in code.

Some are runtime improvements you may benefit from without changing a single line.

And some are still preview/incubator features, which means: interesting to test, but not something to blindly push into production tomorrow. 😉

🔸 TL;DR

▪️ Java 26 brings developer-facing features around HTTP/3, PEM encoding, Structured Concurrency, Lazy Constants, Vector API, and primitive patterns.

▪️ Java 27 continues several previews and adds important runtime/security directions like post-quantum TLS, G1 everywhere, and compact object headers.

▪️ The big theme is not “Java is changing everything”.

▪️ The big theme is: Java keeps modernizing carefully, while preserving stability.

🔸 LANGUAGE: PRIMITIVE PATTERNS GET MORE NATURAL

JEP 530 / JEP 532 improve pattern matching by allowing primitive types in more places

That means instanceof, switch, and primitive conversions become more expressive and safer.

Example idea:

The interesting part is not only...Read More

LESSON of MULTI-LEVEL Fetch with Java champion Vlad Mihalcea ☕🦸‍♂️

Mon, 25 May 2026 13:51:13 -0700

Fetching data is not just about reducing the number of SQL queries.

Sometimes, one query is worse than five.

Today, while following a Virtual JUG session with Vlad Mihalcea, we discussed a classic trap:

At first, the temptation is obvious:

“Let’s fetch everything with one big JOIN.”

But this can quickly become a Cartesian product.

And suddenly, your “optimized query” becomes a data duplication machine. 🧨

🔸 TL;DR

▪️ JOIN FETCH is not bad.

▪️ Fetching several to-many associations at once is dangerous.

▪️ DISTINCT may hide duplicate root entities, but not the cost of duplicated SQL rows.

▪️ Splitting the fetch into several small queries is often cleaner.

▪️ jOOQ MULTISET offers another elegant option: nested results without the flat Cartesian explosion.

🔸 THE JDBC TEMPLATE TRAP

With plain JDBC or JdbcTemplate, the Cartesian product is visible.

The SQL result is flat.

But your object graph is nested.

Java 26 — JEP 529: Vector API (Incubator)

Mon, 25 May 2026 13:01:06 -0700

• The Vector API is Java’s portable SIMD story for data-heavy workloads.

• You write vector operations in Java and let the JVM map them to the best hardware instructions available.

• It is still incubating, so it is best suited to performance-focused code paths and libraries.

#java #java26 #jep529 #vector #performance

Go further with Java certification:

Java👇

https://bit.ly/javaOCP

Spring👇

https://bit.ly/2v7222

SpringBook👇

https://bit.ly/springtify

JavaBook👇

https://bit.ly/jroadmap

☕ Java 26 — JEP 526: Lazy constants (Preview)

Mon, 25 May 2026 12:58:38 -0700

• LazyConstant gives Java a standard way to delay initialization while keeping immutable semantics.

• It helps when object creation is expensive but the value should still behave like a constant after first use.

• This is a cleaner alternative to ad hoc lazy holder code.

#java #java26 #lazyconstants #jep526

Go further with Java certification:

Java👇

https://bit.ly/javaOCP

Spring👇

https://bit.ly/2v7222

SpringBook👇

https://bit.ly/springtify

JavaBook👇

https://bit.ly/jroadmap

🧑‍💻📉 COMPUTER SCIENCE HITS A WALL, NOT A DEAD END

Mon, 25 May 2026 12:53:00 -0700

For 15 years, “learn to code” sounded like one of the safest bets in education.

According to The Washington Post, undergraduate computer science enrollment at four-year U.S. colleges fell 8.1% in fall 2025.

That is a real signal.

But it is not the signal some people will try to sell you.

It does not mean: “don’t become a developer.”

It means: “the easy boom narrative is over.”

AI, layoffs, hiring freezes, market saturation, and uncertainty around entry-level jobs are probably making students and families rethink the automatic “computer science = guaranteed career” equation.

But software is not disappearing.

What is changing is the bar.

🔸 TL;DR

▪️ Computer science enrollment dropped sharply in 2025 📉

▪️ The “learn to code and everything will be fine” era is weaker now

▪️ AI may be scaring some students away from CS 🤖

▪️ But strong developers will still be needed

▪️ The opportunity is shifting from “just code” to “understand systems”

🔸 WHAT THIS DOES NOT MEAN

▪️ It does not mean computer science is useless