concurrent-collections-and-synchronizers SKILL.md skillA
concurrent-collections-and-synchronizers from robsonkades/agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add robsonkades/agent-skills/concurrent-collections-and-synchronizers@git:20261016.c769bd8Pins git:20261016.c769bd8 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- robsonkades/agent-skills
- Path
skills/concurrent-collections-and-synchronizers/SKILL.md- Versions recorded
- 5
- Latest version
- git:20261016.c769bd8, committed Oct 16, 2026
- First version recorded
- Sep 6, 2026
- Size
- 20,698 bytes
- Repository stars
- 3
- License
- Apache-2.0
Choosing between the members of java.util.concurrent once the family is settled, and the parameter that makes it correct: which BlockingQueue and which of its four insert and remove forms, which ConcurrentHashMap atomic replaces a compound action, copy-on-write's cost, latch versus barrier versus phaser versus semaphore, the Condition await loop, and ReentrantLock versus ReentrantReadWriteLock versus StampedLock. Use when computeIfAbsent loads from a database, when IllegalStateException…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Concurrent Collections and Synchronizers ## Purpose Once "use a concurrent collection", "use a queue" or "use a limit" is the decision, this is the next one: **which member of the family, with which parameter, and what breaks when it is wrong.** These failures are rarely exceptions — a consumer that idles with work queued, a limit of 8 that admits 12, a latch nobody counts down, a heap dump full of queue nodes. The _rule_ that a thread-safe collection does not make a sequence atomic belongs to java-thread-safety-contracts; the mechanism it implies is here. Baseline **Java 25**; vendor support status and version-sensitive claims must be checked separately. Before applying that authoring baseline, inspect the target compiler release/toolchain, deployed JDK/vendor/build and existing dependencies. Do not upgrade or enable preview merely to apply this skill. `StructuredTaskScope` is preview in Java 25; route to structured-concurrency for its version-specific API and compiler/runtime flags, and use existing stable coordination APIs when preview is not authorized. ## Workflow 1. **Inspect the invariant and caller lifecycle first.** Reuse code, tests and the supplied context: …
Read the whole file at its exact version.
How to install
mdr add robsonkades/agent-skills/concurrent-collections-and-synchronizers@sha256:ceefcd914b20a9edThe line at the top of this page pins the label git:20261016.c769bd8, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_gmc7o6ueexnutrms)
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Versions
The registry has recorded 5 versions of this file, between Sep 6, 2026 and Oct 16, 2026, about one every 10 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261016.c769bd8 latest | 2026-10-16 | c769bd8 | 20,698 B | A | view · diff |
| git:20260927.9ecadfd | 2026-09-27 | 9ecadfd | 20,035 B | A | view · diff |
| git:20260923.832673e | 2026-09-23 | 832673e | 19,758 B | A | view · diff |
| git:20260911.37b054b | 2026-09-11 | 37b054b | 19,122 B | A | view · diff |
| git:20260906.e6ad4bd | 2026-09-06 | e6ad4bd | 17,876 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (20698 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
robsonkades/agent-skills · 3 stars · license Apache-2.0 · pushed 2026-10-28 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_gmc7o6ueexnutrms GET https://markdownregistry.com/api/v1/resolve?ref=robsonkades/agent-skills/concurrent-collections-and-synchronizers GET https://markdownregistry.com/api/v1/blob/ceefcd914b20a9edd9cce45f76d1b7489f9e473480727cd087f04e2448bf7497
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.