103-java-data-oriented-programming

A set of rules for writing modern Java with a data-oriented style: keep data separate, immutable, validated, and transformed through clear functions.

In plain words
What is it for?
Use it when designing or reviewing Java features that manipulate structured data.
Why use it?
It gives development work a consistent way to represent and process data, making changes easier to trace and validate.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/jabrena/jbang-mcp-examples/103-java-data-oriented-programming
Clone the repo
git clone --depth 1 https://github.com/jabrena/jbang-mcp-examples

Made for: Cursor.

Per session 136 This file is loaded in full into every session.
When invoked 136 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00136 $0.00136
Opus 5 $0.00068 $0.00068
Sonnet 5 $0.00027 $0.00027
Haiku 4.5 $0.00014 $0.00014

Measured yesterday against content hash a6771cb93325, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

103-java-data-oriented-programming scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/103-java-data-oriented-programming.mdc · 18 lines

What it actually says

Data oriented programming pillars:

  • Separate code from data
  • Represent data with generic data structures
  • Data should be immutable
  • Use pure functions to manipulate data
  • Keep data flat and denormalized
  • Keep data generic until it needs to be specific
  • Data integrity is maintained through validation functions
  • Data access should be flexible and generic
  • Data transformation should be explicit and traceable
  • Data flow should be unidirectional
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 18 lines · 136 tokens per session scan A a6771cb93325

Subscribe to this mod's changes

103-java-data-oriented-programming is a cursor rule published in the GitHub repository jabrena/jbang-mcp-examples (1 stars, last pushed 1y ago), licensed Apache-2.0. It adds 136 tokens to every session, about $0.0007 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.