# 144 Java Data Oriented Programming

> Use when you need to apply data-oriented programming best practices in Java — including separating code (behavior) from data structures using records, designing immutable data with pure transformation functions, keeping data flat and denormalized with ID-based references, starting with generic data structures converting to specific types when needed, ensuring data integrity through pure validatio…

- **Type:** Skill
- **Install:** `agentstack add skill-jabrena-cursor-rules-java-144-java-data-oriented-programming`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [jabrena](https://agentstack.voostack.com/s/jabrena)
- **Installs:** 0
- **Category:** [Developer Tools](https://agentstack.voostack.com/c/developer-tools)
- **Latest version:** 0.1.0
- **License:** Apache-2.0
- **Upstream author:** [jabrena](https://github.com/jabrena)
- **Source:** https://github.com/jabrena/cursor-rules-java/tree/main/skills/144-java-data-oriented-programming
- **Website:** https://jabrena.github.io/cursor-rules-java/

## Install

```sh
agentstack add skill-jabrena-cursor-rules-java-144-java-data-oriented-programming
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Java Data-Oriented Programming Best Practices

Apply data-oriented programming in Java: separate data from behavior with records, use immutable data structures, pure functions for transformations, flat denormalized structures with ID references, generic-to-specific type conversion when needed, pure validation functions, and flexible generic data access layers. All transformations should be explicit, traceable, and composed of clear pure functional steps.

**What is covered in this Skill?**

- Separation of concerns: data structures (records, POJOs) vs behavior (utility classes, services)
- Immutability: records, final fields, transformations produce new instances
- Pure data transformations: functions depending only on inputs, no side effects
- Flat and denormalized data: ID references instead of deep nesting
- Generic until specific: Map<String,Object> for dynamic data, convert to records when processing
- Data integrity: pure validation functions returning validation results
- Flexible generic data access: generic CRUD interfaces, interchangeable implementations

**Scope:** The reference is organized by examples (good/bad code patterns) for each core area. Apply recommendations based on applicable examples.

## Constraints

Before applying any data-oriented programming recommendations, ensure the project compiles. Compilation failure is a blocking condition. After applying improvements, run full verification.

- **MANDATORY**: Run `./mvnw compile` or `mvn compile` before applying any change
- **SAFETY**: If compilation fails, stop immediately — do not proceed until resolved
- **VERIFY**: Run `./mvnw clean verify` or `mvn clean verify` after applying improvements
- **BEFORE APPLYING**: Read the reference for detailed good/bad examples, constraints, and safeguards for each data-oriented programming pattern

## When to use this skill

- Improve the code with Data-Oriented Programming
- Apply Data-Oriented Programming
- Refactor the code with Data-Oriented Programming
- Apply Data-Oriented Programming
- Refactor the code with Data-Oriented Programming
- Apply Data-Oriented Programming

## Workflow

1. **Compile project before data-oriented changes**

Run `./mvnw compile` or `mvn compile` and stop immediately if compilation fails.

2. **Read data-oriented reference and assess model design**

Read `references/144-java-data-oriented-programming.md` and identify candidates for data/behavior separation and immutable transformations.

3. **Apply data-oriented refactorings**

Implement selected improvements using records, pure transformation functions, flat structures, and explicit validation.

4. **Verify with full build**

Run `./mvnw clean verify` or `mvn clean verify` after applying improvements.

## Reference

For detailed guidance, examples, and constraints, see [references/144-java-data-oriented-programming.md](references/144-java-data-oriented-programming.md).

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [jabrena](https://github.com/jabrena)
- **Source:** [jabrena/cursor-rules-java](https://github.com/jabrena/cursor-rules-java)
- **License:** Apache-2.0
- **Homepage:** https://jabrena.github.io/cursor-rules-java/

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-jabrena-cursor-rules-java-144-java-data-oriented-programming
- Seller: https://agentstack.voostack.com/s/jabrena
- Browse the marketplace: https://agentstack.voostack.com/browse

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