# Flyweight Design Pattern — Java Example

**Pattern:** Structural → Flyweight
**Article:** https://ankurm.com/flyweight-design-pattern-java/

## What this example shows

A forest of 1,000 trees shares just 3 `TreeType` flyweight objects (one per species) instead of allocating a new heavy object per tree. `TreeType` holds the intrinsic (shared) state — name, color, texture. `Tree` holds only the extrinsic (unique) state — x/y position — plus a reference to its shared `TreeType`. `TreeFactory` is the pool manager: `Map.computeIfAbsent()` returns an existing flyweight or creates and caches one.

## How to run

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

Requires Java 25.

## Post Section ↔ File Mapping

| Post Section | File(s) |
|---|---|
| Step 1 — The Flyweight (TreeType) | `TreeType.java` |
| Step 2 — The Factory (TreeFactory) | `TreeFactory.java` |
| Step 3 — The Context (Tree) | `Tree.java` |
| Putting the Forest Together | `Main.java` |

Note: the "Flyweight in the JDK: String Pool and Integer Cache" and "Measuring the Benefit" snippets are illustrative only — they are not part of this repository's runnable example.

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