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Practical guides on software architecture, system design, developer tools, tutorials, and the technology trends shaping how we build.
Latest from Debug
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02 – Factory Method Pattern
Factory Method Pattern in Java: Delegating Object Creation The Problem You need to create objects, but the exact type to instantiate should be decided by subclasses or configuration — not hardcoded with new. The Factory Method pattern defines an interface for creating an object, letting subclasses decide which class to instantiate. Diagram Java Example Quarkus Example In Quarkus, Factory Method often becomes…
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01 – Singleton Pattern
Singleton Pattern in Java: Ensuring a Single Instance The Problem Sometimes you need exactly one instance of a class across your whole application — a configuration manager, a connection pool, a logger. The Singleton pattern guarantees a class has only one instance and provides a global point of access to it. Diagram Java Example (thread-safe, lazy) The classic double-checked locking is safe…
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Design Patterns in Java: A Practical Introduction
What Are Design Patterns? A design pattern is a reusable, proven solution to a recurring design problem — not a finished piece of code you copy-paste, but a template for how to structure classes and objects to solve a specific kind of problem. The idea was popularized by the “Gang of Four” (Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides) in their 1994 book Design…