Weekly Recap – June 15th, 2025

SQL, Kotlin, Java Basics, Spring Boot, and JavaScript

This past week, I focused mostly on SQL here on Substack, I covered how to build search features with LIKE and wildcards, reshape row data into columns for pivot tables, calculate percent changes between rows, and break big queries into smaller parts using CTEs. I also posted one Kotlin article on how enum classes connect to companion code on the JVM.

On Medium, I kept a steady mix of the usual topics. Java got a few beginner-friendly posts on try-catch blocks, converting between strings and numbers, and drawing patterns with nested loops. For Spring Boot, I wrote about working with profiles, external config servers, and SQLite, along with some practical examples like auto-wiring collections and writing custom validators. I also published some JavaScript guides on input events, keyboard handling, URL objects, and how import.meta shows up in real code. A few were written with beginners in mind, which I always enjoy making time for.

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Substack Exclusive

Build a Search Feature with SQL LIKE and Wildcards

Turning Rows Into Columns To Build Pivot Tables In SQL

Calculating Percent Change Between Rows in SQL

Breaking Big Queries into Manageable Parts with CTEs

Kotlin Enum Classes and the Companion JVM Code

Medium Articles

Java Topics

• Handling Basic Errors With Try and Catch Blocks in Java for Beginners

• Converting Between Strings and Numbers in Java

• Printing Patterns with Nested Loops in Java

Spring Boot Topics

• Making a Secure Download Link System with Spring Boot

• Using Profiles to Separate Dev and Test Beans in Spring Boot

• Connecting Spring Boot to an External Configuration Server

• Writing a Custom Validator in Spring Boot With Bean Validation

• Auto-Wiring Collections of Beans in Spring Boot

• Setting Up Content Negotiation in Spring Boot

• Using Spring Boot with SQLite for Lightweight Apps

JavaScript Topics

• Measuring Paint Timings with JavaScript First Contentful Paint API

• Handling Keyboard Input with JavaScript KeyboardEvent Properties

• Using JavaScript URL Objects to Work with Query Parameters

• Capturing Stack Traces With Error Objects in JavaScript

• Handling Scroll Events Efficiently with Passive Listeners in JavaScript

• Why import.meta Matters in Real JavaScript Projects

• Capturing Live User Input with JavaScript Input Events

Kotlin Topics

• How Kotlin Handles Type Erasure on the JVM

• Kotlin Range Operators and the JVM Bytecode They Compile To

• What Kotlin Does Internally With lateinit

• How Kotlin Uses Smart Casts During Compilation

Right now, I’m working on a mix of new posts across Spring Boot, Java, and Kotlin as usual. There’ll be some JavaScript content this week too, but I may swap a couple of those slots with beginner-friendly Gradle topics. I’ve been going through a few ideas that walk through how builds actually work, for anyone new to managing dependencies or setting up Java projects from scratch. Should be a good balance of practical walkthroughs and a few focusing on how things run behind the scenes.