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.
npx agentmods add skills/jabrena/cursor-rules-examples/125-java-concurrencynpx skills add jabrena/cursor-rules-examples --skill 125-java-concurrencygit clone --depth 1 https://github.com/jabrena/cursor-rules-examplesWhat 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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00078 | $0.00643 |
| Opus 5 | $0.00039 | $0.00321 |
| Sonnet 5 | $0.00016 | $0.00129 |
| Haiku 4.5 | $0.00008 | $0.00064 |
Grade A, and why
125-java-concurrency 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.
How it starts
The opening of the file, as written. The whole thing — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Java rules for Concurrency objects
Identify and apply Java concurrency best practices to improve thread safety, scalability, and maintainability by using modern java.util.concurrent utilities and virtual threads.
What is covered in this Skill?
- Thread safety fundamentals:
ConcurrentHashMap,AtomicInteger,ReentrantLock,ReadWriteLock, Java Memory Model ExecutorServicethread pool configuration: sizing, keep-alive, bounded queues, rejection policies, graceful shutdown- Producer-Consumer and Publish-Subscribe patterns with
BlockingQueue CompletableFuturefor non-blocking async composition (thenApply/thenCompose/exceptionally/orTimeout)- Immutability and safe publication (
volatile, static initializers) - Lock contention and false-sharing performance optimization
- Virtual threads (
Executors.newVirtualThreadPerTaskExecutor()) for I/O-bound scalability ScopedValueoverThreadLocalfor immutable cross-task data- Cooperative cancellation and
InterruptedExceptiondiscipline - Backpressure with bounded queues and
CallerRunsPolicy - Deadlock avoidance via global lock ordering and
tryLockwith timeouts - ForkJoin/parallel-stream discipline for CPU-bound work
- Virtual-thread pinning detection (JFR
VirtualThreadPinned) - Thread naming and
UncaughtExceptionHandlerobservability - Fit-for-purpose primitives:
LongAdder,CopyOnWriteArrayList,StampedLock,Semaphore,CountDownLatch,Phaser
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 concurrency changes, ensure the project compiles. If compilation fails, stop immediately — compilation failure is a blocking condition. After applying improvements, run full verification.
- MANDATORY: Run
./mvnw compileormvn compilebefore applying any change - SAFETY: If compilation fails, stop immediately — compilation failure is a blocking condition that prevents any further processing
- VERIFY: Run
./mvnw clean verifyormvn clean verifyafter applying improvements - BEFORE APPLYING: Read the reference for detailed good/bad examples, constraints, and safeguards for each concurrency pattern
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 2d ago First seen · 49 lines · 78 tokens per session scan A 78ade00585ef
125-java-concurrency is a skill published in the GitHub repository jabrena/cursor-rules-examples (2 stars, last pushed 6d ago), licensed Apache-2.0. It adds 78 tokens to every session and 643 once invoked, about $0.0004 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.
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