java-spring

A development guide for Java 21 or newer projects using Spring Boot, a Java framework for building applications and services. It lists the project's tools and points to more specific rules for each type of work.

In plain words
What is it for?
Use it when building or modifying REST endpoints, services, database access, messaging, security, external integrations, resilience, logging, or tests in a Spring Boot application.
Why use it?
It helps an agent choose the right conventions before changing controllers, business logic, data access, integrations, or tests. This reduces inconsistent implementation across the project.

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/goranerhartic/cursor-development-rules/java-spring
Clone the repo
git clone --depth 1 https://github.com/GoranErhartic/cursor-development-rules

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 835 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00000 $0.00835
Opus 5 $0.00000 $0.00417
Sonnet 5 $0.00000 $0.00167
Haiku 4.5 $0.00000 $0.00084

Measured 2d ago against content hash cb3f707aa57e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

java-spring 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 2d ago.

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/languages/java/java-spring.mdc · 73 lines

How it starts

The opening of the file, as written. The whole thing — 73 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Java + Spring Boot Development Guide

Stack

Layer Technology
Runtime Java 21+
Framework Spring Boot 3
Build Maven or Gradle
Validation Jakarta Bean Validation
Data Spring Data JPA
Security Spring Security
Messaging Spring Cloud Stream (Kafka, RabbitMQ)
Resilience Resilience4j
Testing JUnit 5, AssertJ, Mockito, WireMock
Logging SLF4J, Logback, MDC

Rule Routing

Consult these rules based on what you are working on:

Quick Reference

  • Build/modify REST endpoint: languages/java/controllers.mdc, languages/java/validation.mdc, languages/java/error-handling.mdc
  • Build service/business flow: languages/java/cqrs.mdc, languages/java/bff-architecture.mdc, languages/java/testing.mdc
  • Data access updates: languages/java/jpa.mdc, languages/java/aggregation.mdc
  • External integration and resilience: languages/java/http-clients.mdc, languages/java/resilience.mdc, languages/java/logging.mdc

API & Controllers

  • REST controllers, ResponseEntity, OpenAPI → languages/java/controllers.mdc
  • Request validation (Bean Validation) → languages/java/validation.mdc
  • Input sanitization (SQL injection, XSS, path traversal) → languages/java/input-sanitization.mdc

BFF & Architecture

  • BFF patterns, Clean Architecture, Vertical Slice → languages/java/bff-architecture.mdc
  • CQRS commands, queries, handlers, dispatcher → languages/java/cqrs.mdc
  • Response aggregation, parallel calls, CompletableFuture → languages/java/aggregation.mdc

Data & Persistence

  • JPA repositories, entities, transactions → languages/java/jpa.mdc

Cross-Cutting

  • Code quality, Java 25 idioms, records, sealed classes → languages/java/code-quality.mdc
  • Formatting (parameter alignment, line breaking) → languages/java/formatting.mdc
  • Error handling, Result pattern, ProblemDetail (RFC 7807) → languages/java/error-handling.mdc
  • Logging (SLF4J, Logback, MDC, Micrometer) → languages/java/logging.mdc
  • Security (secrets, HTTPS, headers, CORS) → languages/java/security.mdc
  • Auth (JWT, method security, RBAC) → languages/java/auth.mdc
  • Resilience4j (retry, circuit breaker, rate limiter) → languages/java/resilience.mdc
  • RestClient, declarative HTTP interfaces → languages/java/http-clients.mdc
  • Messaging (Kafka, RabbitMQ, functional bindings) → languages/java/messaging.mdc
  • Testing (JUnit 5, Mockito, WireMock, ArchUnit) → languages/java/testing.mdc
  • Dependencies (Maven BOM, versioning, licensing) → languages/java/dependencies.mdc

Read the full file on GitHub · 73 lines

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. 2d ago First seen · 73 lines · 0 tokens per session scan A cb3f707aa57e

Subscribe to this mod's changes

java-spring is a cursor rule published in the GitHub repository GoranErhartic/cursor-development-rules (19 stars, last pushed 6mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 835 tokens. 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 2026-08-30.