Java

Java is a statically typed, object-oriented language that compiles to bytecode and runs on the Java Virtual Machine, so the same build runs on any platform with a JVM. Its mature ecosystem includes the Collections framework, JDBC, JPA with Hibernate for data access and Spring Boot for web services. Java remains a mainstay for enterprise backends and large data systems, with a new long-term support release every two years.

74 articles

23/04/2022 12 min read

Practice: Model a Library System with OOP (Part 1: Domain Design)

Executive Summary: Part 1 of the library system project designs a Java domain model across model and event…
20/03/2022 8 min read

Sealed Classes and Pattern Matching Foundations

Executive Summary: Sealed classes and interfaces in Java list their permitted subtypes, so the compiler knows every variant.…
20/02/2022 8 min read

Records in Java: Immutable Data Carriers Done Right

Executive Summary: A Java record declares an immutable data carrier in one line, and the compiler generates the…
16/01/2022 8 min read

Enums in Java: From Basics to EnumSet and EnumMap

Executive Summary: Java enums define a fixed set of singleton constants that can carry fields, constructors, and per-constant…
01/01/2022 8 min read

Abstract Classes vs Interfaces in Java

Executive Summary: Use an abstract class when related classes share state or a fixed workflow, and an interface…
21/11/2021 9 min read

The Object Class: equals, hashCode, toString, and clone

Executive Summary: Every Java class inherits equals, hashCode, toString, and clone from Object, and the defaults use identity.…
17/10/2021 9 min read

Inheritance and Polymorphism in Java

Executive Summary: In Java, a subclass inherits from its parent, can override its methods, and runs the overridden…
18/09/2021 8 min read

Encapsulation, Access Modifiers, and Packages in Java

Executive Summary: Encapsulation in Java means keeping fields private and exposing behavior through methods that enforce the object’s…
04/09/2021 9 min read

Java Constructors and the this Keyword: Building Objects That Start Valid

Executive Summary: Java constructors initialize objects at creation, and good ones make invalid objects impossible. I cover classes…
15/08/2021 10 min read

Gradle for Java Projects: Builds, Tasks, and Kotlin DSL

Executive Summary: Gradle builds Java projects from a build.gradle.kts file using plugins, repositories, dependencies, and a toolchain that…
01/08/2021 10 min read

Practice: Build a Number Guessing Game in Java

Executive Summary: This beginner project builds a Java number guessing game with Random, a Scanner input loop, replay,…
20/07/2021 10 min read

Maven for Java Projects: From pom.xml to Build Lifecycle

Executive Summary: Maven builds Java projects from a pom.xml that declares coordinates, dependencies, and plugins. I cover transitive…
03/07/2021 10 min read

Practice: Build a CLI Calculator in Java

Executive Summary: This practice project builds a single-file Java CLI calculator with one-shot and interactive modes and switch-expression…
30/05/2021 8 min read

Arrays and Strings in Java (with StringBuilder)

Executive Summary: Java arrays are fixed-length containers with helpers in java.util.Arrays, and Strings are immutable. I cover creating,…