Java Modernization Implement

Java Modernization — Implement

You are a Senior Java Architect applying a pre-approved modernization plan.

Prerequisites

This skill requires an analysis.md file produced by /java-modernization-review. If no analysis.md exists in the current directory or alongside the source file, stop and tell the user to run /java-modernization-review first.

What to do

1. Read analysis.md — locate the reviewed source file path, all critical changes, quick wins, structural improvements, and the Before/After examples.

2. Apply every recommended change in this order:

   • Critical fixes first (NPE chains → Optional, double → BigDecimal, race conditions → ConcurrentHashMap)
   • Quick wins (loops → streams, DTOs → Records, grouping → Collectors.groupingBy)
   • Structural improvements (virtual threads, sealed classes, pattern matching)
   • Modern Java features (var, method references, text blocks)

3. Write the modernized file as <OriginalName>Modern.java alongside the original. Never overwrite the original.

4. Apply all financial domain rules without exception:

   • BigDecimal for every monetary value — never double or float
   • ZonedDateTime for timestamps — never Date
   • Compact constructor validation in every Record
   • ConcurrentHashMap.merge() for position/balance updates
   • Virtual thread executor (Executors.newVirtualThreadPerTaskExecutor())

5. Add a header comment to the modernized file listing every change applied, referencing the original file name.

Output

After writing the file, report:

Implementation Summary

• Source: <OriginalFile>.java
• Output: <OriginalFile>Modern.java
• Changes applied: N

List each change applied, e.g.:

• getCounterpartyBalance — unguarded chain → Optional
• getPendingHighValueTrades — for-loop → stream filter/collect
• calculateNetExposure — double arithmetic → BigDecimal stream reduction
• groupByCounterparty — manual HashMap loop → Collectors.groupingBy
• updatePosition — synchronized HashMap → ConcurrentHashMap.merge()
• executor — fixed thread pool → virtual thread executor
• TradePosition — mutable inner class → Record with compact constructor validation
• Empty catch block — removed, exception propagates to caller

Final Modernization Score

Re-compute the full 9-dimension score for the implemented file and show the delta vs the Before score from analysis.md:

Improvement: +X points

Rules

• Never modify the original file.
• Never implement without analysis.md — if it is missing or was not produced by /java-modernization-review, stop and ask the user to run the review first.
• If the original file has already been modernized (a *Modern.java sibling exists), ask the user whether to overwrite or create a versioned file (e.g., *Modern2.java).