---
phase: quick
plan: 001
subsystem: infra
tags: [jdk, loom, virtual-threads, jdbc, quill]

# Dependency graph
requires: []
provides:
  - Updated JDK requirement documentation (21+ for Loom)
affects: []

# Tech tracking
tech-stack:
  added: []
  patterns: []

key-files:
  created: []
  modified:
    - .planning/research/STACK.md

key-decisions:
  - "JDK 21+ required for Loom virtual threads benefiting JDBC blocking ops"
  - "ZIO fibers and JVM virtual threads are complementary, not competing"

patterns-established: []

# Metrics
duration: 1min
completed: 2026-02-05
---

# Quick Task 001: Update JDK Requirement Summary

**JDK requirement updated to 21+ with Loom virtual threads rationale for JDBC blocking operations in Quill**

## Performance

- **Duration:** <1 min
- **Started:** 2026-02-05T12:07:20Z
- **Completed:** 2026-02-05T12:07:56Z
- **Tasks:** 1
- **Files modified:** 1

## Accomplishments
- Updated JDK version requirement from 17+ to 21+ in Language & Runtime table
- Added rationale explaining Loom virtual threads benefit for JDBC blocking operations
- Clarified that ZIO fibers and JVM virtual threads are complementary, not competing

## Task Commits

Each task was committed atomically:

1. **Task 1: Update JDK requirement in research/STACK.md** - `64dcded` (docs)

## Files Created/Modified
- `.planning/research/STACK.md` - Updated JDK requirement and added Loom rationale note

## Decisions Made
- JDK 21+ is the new baseline (was 17+) - both are LTS releases
- Rationale focuses on JDBC blocking operations which benefit from Loom virtual threads
- Explicitly clarifies that ZIO's fiber system is complementary to JVM virtual threads

## Deviations from Plan
None - plan executed exactly as written.

## Issues Encountered
None

## User Setup Required
None - documentation-only change.

## Next Phase Readiness
- Stack documentation now accurately reflects JDK 21+ requirement
- Ready for Phase 2 planning

---
*Quick Task: 001*
*Completed: 2026-02-05*