Java

This Java programming series goes from first classes to production Spring Boot apps. It has more than seventy posts, so it works as a full course.

Early posts cover the language and collections. Later, JDBC fundamentals and JPA and Hibernate add data access. Finally, testing Spring Boot apps ties it all together.

74 articles

23/03/2024 13 min read

Practice: Build a Small Network Client or File Tool

Executive Summary: This practice project builds LinkCheck, a Java tool that reads URLs from a file, fetches each…
25/02/2024 12 min read

Modern Java Features: var, Text Blocks, and Pattern Matching

Executive Summary: Modern Java gives you var for local type inference, text blocks for multi-line strings, switch expressions…
12/02/2024 4 min read

Spring Boot REST API

Executive Summary: Java REST services without clear layering end up with fat controllers and brittle contracts. Here I…
05/02/2024 6 min read

Spring Boot Auto-Configuration: Your First REST Endpoint, Explained

Executive Summary: Spring Boot auto-configuration sets up the server, dependency injection, and JSON handling, so a REST endpoint…
28/01/2024 10 min read

Networking Basics in Java: Sockets and HTTP Clients

Executive Summary: Java networking ranges from raw TCP sockets to the built-in HttpClient. I cover ServerSocket and Socket…
20/01/2024 10 min read

Dependency Injection Concepts in Java

Executive Summary: Dependency injection means a class receives its collaborators, usually as interfaces through the constructor, instead of…
07/01/2024 10 min read

Serialization in Java: How It Works and Why to Avoid It

Executive Summary: Java serialization turns an object graph into bytes through Serializable, with serialVersionUID and transient controlling compatibility…
13/12/2023 4 min read

Understanding JVM Internals: From Source Code to Runtime

Executive Summary: Treating the JVM as a black box makes tuning and production debugging guesswork. Here I walk…
02/12/2023 11 min read

Java Modules (JPMS): Basics and Migration

Executive Summary: Java modules group packages behind a module-info.java file that declares what a module requires, exports, and…
04/11/2023 11 min read

Reflection in Java: Inspecting and Modifying Classes at Runtime

Executive Summary: Reflection lets Java code inspect and call classes at runtime through Class, Method, Field, and Constructor…
24/09/2023 10 min read

Annotations in Java: Built-in, Custom, and Retention Policies

Executive Summary: Java annotations are types declared with @interface whose elements hold compile-time constants. I cover built-ins like…
02/09/2023 12 min read

Practice: Process and Analyze a CSV with Streams

Executive Summary: This practice project analyzes a sales CSV with Java streams. You model rows as a validated…
12/08/2023 11 min read

NIO.2: Path, Files, and Modern File Handling

Executive Summary: NIO.2’s Path and Files replace string-built file paths and verbose IO code. I’ll cover building and…
08/07/2023 10 min read

File I/O in Java: Streams, Readers, and Writers

Executive Summary: Classic Java file I/O splits into byte streams for binary data and readers and writers for…