102-java-functional-programming

Java coding rules that encourage a functional programming style, such as immutable objects, pure functions, functional interfaces, lambdas, and streams. Functional programming emphasizes transformations with limited changes to shared state.

In plain words
What is it for?
Use them when adding or reviewing Java code where immutability, pure functions, lambdas, interfaces, or streams are appropriate.
Why use it?
They make the preferred Java style explicit, helping agents write code that avoids unnecessary mutation and follows the project's functional programming conventions.

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/102-java-functional-programming
Clone the repo
git clone --depth 1 https://github.com/jabrena/jbang-mcp-examples

Made for: Cursor.

Per session 90 This file is loaded in full into every session.
When invoked 90 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 $0.00090 $0.00090
Opus 5 $0.00045 $0.00045
Sonnet 5 $0.00018 $0.00018
Haiku 4.5 $0.00009 $0.00009

Measured yesterday against content hash 6aabe8e58ffe, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

102-java-functional-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/102-java-functional-programming.mdc · 15 lines

What it actually says

functional_programming_guidelines:

  • Try to use immutable objects
  • Try to not mutate the state of the objects
  • Try to use pure functions
  • Try to use functional interfaces
  • Try to use lambda expressions
  • Try to use streams
  • Try to use functional programming paradigms
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 · 15 lines · 90 tokens per session scan A 6aabe8e58ffe

Subscribe to this mod's changes

102-java-functional-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 90 tokens to every session, about $0.0005 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.