# Builder Design Pattern — Java Example

**Pattern:** Creational → Builder
**Article:** https://ankurm.com/builder-design-pattern-java/

## What this example shows

An immutable `HttpRequest` assembled step by step instead of through a constructor with a dozen optional parameters. `HttpRequest` is the product — built once, never mutated afterward. `HttpClientConfig` is a director-style helper that encapsulates common request configurations so callers don't repeat the same builder calls. `Main` wires it together and shows the fluent builder chain in action.

## How to run

```bash
javac builder/*.java -d out/builder
java -cp out/builder builder.Main
```

Requires Java 25.

## Post Section ↔ File Mapping

| 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.

Article: https://ankurm.com/builder-design-pattern-java/
All patterns: https://ankurm.com/design-patterns-java/