Sync Factory Method, Abstract Factory, Builder, Prototype to Java 25; fix post/code mismatches

README.md

@@ -1,6 +1,6 @@
 # GoF Design Patterns in Java
 
-Complete runnable Java 17 implementations of all 23 Gang of Four design patterns.
+Complete runnable Java 25 implementations of all 23 Gang of Four design patterns.
 Each pattern has a dedicated article at [ankurm.com](https://ankurm.com/gof-design-patterns-java/)
 with a UML diagram, step-by-step explanation, and console output.
 
@@ -38,7 +38,7 @@ design-patterns/
 
 ## Prerequisites
 
-- Java 17+ (Eclipse Temurin recommended)
+- Java 25+ (Eclipse Temurin recommended)
 - No build tool required — plain `javac` / `java`
 
 ## Run any pattern
@@ -83,6 +83,81 @@ java -cp out\strategy strategy.Main
 | Template Method | Behavioral | https://ankurm.com/template-method-design-pattern-java/ |
 | Visitor | Behavioral | https://ankurm.com/visitor-design-pattern-java/ |
 
+## Post ↔ Code Mapping
+
+Each article is split into multiple runnable parts. This section maps every post section to the exact file(s) in this repository, so you can jump straight from "what I just read" to "the file that implements it." Updated pattern-by-pattern as each article is verified against Java 25.
+
+### Factory Method (`01-creational/factory-method/`)
+
+| Post Section | File(s) |
+|---|---|
+| The Problem: Object Creation Leaks Into Business Logic | `NotificationService.java` (anti-pattern shown for contrast — not called by `Main`) |
+| Part 1 — The Notification Interface | `Notification.java` |
+| Part 2 — The Concrete Notification Classes | `EmailNotification.java`, `SmsNotification.java`, `PushNotification.java` |
+| Part 3 — The NotificationSender Class | `NotificationSender.java` |
+| Part 4 — The Concrete Sender Subclasses | `EmailSender.java`, `SmsSender.java`, `PushSender.java` |
+| Part 5 — Running It: Client Code and Output | `Main.java` |
+| Adding a New Channel (Slack) | `SlackNotification.java`, `SlackSender.java` |
+
+Run it:
+```bash
+javac 01-creational/factory-method/*.java -d out/factory-method
+java -cp out/factory-method factorymethod.Main
+```
+
+### Abstract Factory (`01-creational/abstract-factory/`)
+
+| Post Section | File(s) |
+|---|---|
+| Part 1 — The Abstract Products: Button and TextField | `Button.java`, `TextField.java` |
+| Part 2 — The Concrete Products (Light family) | `LightButton.java`, `LightTextField.java` |
+| Part 2 — The Concrete Products (Dark family) | `DarkButton.java`, `DarkTextField.java` |
+| Part 3 — The Abstract Factory: UIFactory Interface | `UIFactory.java` |
+| Part 4 — The Concrete Factories | `LightThemeFactory.java`, `DarkThemeFactory.java` |
+| Part 5 — The Client: Application | `Application.java`, `Main.java` |
+
+Run it:
+```bash
+javac 01-creational/abstract-factory/*.java -d out/abstract-factory
+java -cp out/abstract-factory abstractfactory.Main
+# or, for the dark theme family:
+java -Dapp.theme=dark -cp out/abstract-factory abstractfactory.Main
+```
+
+### Builder (`01-creational/builder/`)
+
+| Post Section | File(s) |
+|---|---|
+| Part 1 — The Product: HttpRequest (Immutable) | `HttpRequest.java` |
+| Part 2 — The Director: Encapsulating Common Configurations | `HttpClientConfig.java` |
+| Part 3 — Using the Builder: Client Code | `Main.java` |
+
+Note: the Lombok `@Builder` example and the JDK standard-library snippets (`HttpRequest.newBuilder()`, `StringBuilder`, `ProcessBuilder`) are illustrative only — they are not part of this repository's runnable example.
+
+Run it:
+```bash
+javac 01-creational/builder/*.java -d out/builder
+java -cp out/builder builder.Main
+```
+
+### Prototype (`01-creational/prototype/`)
+
+| Post Section | File(s) |
+|---|---|
+| Part 1 — The Prototype Interface: Copyable | `Copyable.java` |
+| Part 2 — The Nested Object: DocumentMetadata | `DocumentMetadata.java` |
+| Part 3 — The Concrete Prototype: Document | `Document.java` |
+| Part 4 — The Prototype Registry: DocumentRegistry | `DocumentRegistry.java` |
+| Part 5 — Using the Prototype: Client Code | `Main.java` |
+
+Note: the `ShallowVsDeepDemo` snippet (shallow vs. deep copy) and the `Cloneable`-based example are illustrative only — they are not part of this repository's runnable example.
+
+Run it:
+```bash
+javac 01-creational/prototype/*.java -d out/prototype
+java -cp out/prototype prototype.Main
+```
+
 ## Reference
 
 - *Design Patterns: Elements of Reusable Object-Oriented Software* — Gamma, Helm, Johnson, Vlissides