Skillshub java-concurrency

Modern concurrency patterns using Virtual Threads and Structured Concurrency. Use when implementing Java Virtual Threads (Java 21), Structured Concurrency with StructuredTaskScope, CompletableFuture pipelines, or debugging race conditions. (triggers: **/*.java, Thread, Executor, synchronized, lock, CompletableFuture, StructuredTaskScope, VirtualThread, AtomicInteger, async, race condition)

install

source · Clone the upstream repo

git clone https://github.com/ComeOnOliver/skillshub

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/ComeOnOliver/skillshub "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/HoangNguyen0403/agent-skills-standard/java-concurrency" ~/.claude/skills/comeonoliver-skillshub-java-concurrency && rm -rf "$T"

manifest: skills/HoangNguyen0403/agent-skills-standard/java-concurrency/SKILL.md

source content

Java Concurrency

Priority: P1 (HIGH)

Modern concurrent programming emphasizing Virtual Threads (Loom) and safety.

Implementation Guidelines

Virtual Threads (Java 21): Use for high-throughput I/O.
```
Executors.newVirtualThreadPerTaskExecutor()
```
.
Structured Concurrency: Use
```
StructuredTaskScope
```
to treat related tasks as a single unit (Scope, Fork, Join).
Immutability: Share immutable data between threads to avoid race conditions.
CompletableFuture: Use for composing async pipelines (if not using Virtual Threads).
Atomic Variables: Use
```
AtomicInteger
```
,
```
LongAdder
```
for simple counters.
Locks: Prefer
```
ReentrantLock
```
/
```
ReadWriteLock
```
over
```
synchronized
```
for fine-grained control.
Thread Safety: Document
```
@ThreadSafe
```
or
```
@NotThreadSafe
```
.

Anti-Patterns

No new Thread(): Use Executors or virtual threads; never create threads manually.
No Pooling Virtual Threads: Virtual threads are cheap; never pool them.
No Blocking in synchronized: Pins carrier thread (Loom pitfall); use ReentrantLock instead.
No Shared Mutable State: Share only immutable data between threads.
No Thread.stop/suspend: Deprecated; use interruption or cancellation instead.

References

StructuredTaskScope & VirtualThread Examples