docs: Java 21 modernization rollup audit

[devin-ai-integration]

Description of the Change

Adds MODERNIZATION-ROLLUP.md, the Phase 3 audit document for the Java 11 → Java 21 modernization effort. The document inventories the foundation, package, SAM-threshold, and rollup PRs; records before/after aggregate metrics; includes the Phase 3 completeness-gate command output; and consolidates the remaining human-review items.

Final gate recorded in the document:

find src -name "*.java" | wc -l
# 1727

grep -rn "new Runnable()" --include="*.java" src/ | wc -l
# 3

grep -rn "new ActionListener()" --include="*.java" src/ | wc -l
# 7

ant -f release-build.xml
# BUILD SUCCESSFUL; 435 tests, 0 failures, 0 errors, 7 skipped

Why Should This Be In Core?

This is the requested rollup audit artifact for a federal-grade Java LTS migration. It gives reviewers a single source of truth for PR inventory, modernization metrics, verification status, and intentionally retained edge cases.

Benefits

• Documents all open Java 21 migration PRs and their branches.
• Shows the final repository-wide gate thresholds are satisfied (Runnable=3, ActionListener=7).
• Preserves human-review rationale for the remaining SAM grep matches.
• Captures local build/test verification under JDK 21.

Potential Drawbacks

• The rollup document depends on the migration PR set and SAM threshold PR remaining available for review.
• CI is not configured on the fork, so the rollup records local Ant build verification rather than GitHub checks.

Applicable Issues

N/A

Link to Devin session: https://app.devin.ai/sessions/36287b7c637242dba0a6a659737d5402
Requested by: @jakexcosme

---

Devin Review

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[devin-ai-integration]

Original prompt from Jake

#``# Overview

Migrate COG-GTM/WorldWindJava from Java 11 to Java 21 LTS. This is a federal-grade, zero-breakage migration with atomic per-package PRs, full test verification before and after, and a rollup audit document. Use parallel child sessions to accelerate. All PRs target the fork's develop branch.

#``# PHASE 0: Pre-Migration Baseline (Sequential — MUST complete before anything else)

#``#``# Step 0.1: Capture Pre-Migration Baseline Metrics
Before ANY changes, on the develop branch with JDK 11:

`#` File count
find src -name "*.java" | wc -l
`#` Anonymous inner class counts
grep -rn "new Runnable()" --include="*.java" src/ | wc -l
grep -rn "new ActionListener()" --include="*.java" src/ | wc -l
grep -rn "new Callable()" --include="*.java" src/ | wc -l
grep -rn "new MouseListener()" --include="*.java" src/ | wc -l
grep -rn "new KeyListener()" --include="*.java" src/ | wc -l  
grep -rn "new ChangeListener()" --include="*.java" src/ | wc -l
grep -rn "new PropertyChangeListener()" --include="*.java" src/ | wc -l
grep -rn "new WindowListener()" --include="*.java" src/ | wc -l
`#` instanceof pattern-match candidates
grep -rn "instanceof " --include="*.java" src/ | wc -l
`#` Deprecated usage
grep -rn "`@`Deprecated" --include="*.java" src/ | wc -l
grep -rn "new Integer(" --include="*.java" src/ | wc -l
grep -rn "new Double(" --include="*.java" src/ | wc -l
grep -rn "new Float(" --include="*.java" src/ | wc -l
grep -rn "new Long(" --include="*.java" src/ | wc -l
grep -rn "new Boolean(" --include="*.java" src/ | wc -l

Save all counts to a file BASELINE-METRICS.txt at the repo root. This is your "before" snapshot.

#``#``# Step 0.2: Run the existing test suite under JDK 11

ant -f release-build.xml

Record pass/fail counts. This establishes that the test suite is green BEFORE migration.

#``# PHASE 1: Foundational JDK 21 Retarget PR (Sequential — Wave 0)

#``#``# Step 1.1: Create branch devin/java21-foundation
Make these changes ONLY (no code changes):

1. **`release-... (12653 chars truncated...)

[devin-ai-integration]

🤖 Devin AI Engineer

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✅ I will automatically:

• Address comments on this PR that start with 'DevinAI' or '@devin'.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

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[devin-ai-integration]

Java 21 E2E verification results

Ran a clean local JDK 21 Ant release build on devin/java21-rollup, verified the full JUnit suite and release artifacts, then ran a Java 21 runtime probe against the built worldwind.jar and worldwindx.jar.

Escalation/caveat: the GUI demo smoke was not fully verified. ./run-demo.bash gov.nasa.worldwindx.examples.HelloWorldWind loaded the built demo class, then JOGL/nativewindow failed under Xvfb with Nativewindow X11 IOError; I treated that as failed/blocked, not a pass. PR #23 still has no configured GitHub CI checks, so this is local/manual verification.

• passed — Clean JDK 21 build: ant -f release-build.xml clean build exited 0 and logged BUILD SUCCESSFUL.
• passed — JUnit totals: 435 tests, 0 failures, 0 errors, 7 skipped.
• passed — Migration gate: 1727 Java files, new Runnable() count 3, new ActionListener() count 7.
• passed — Artifacts: worldwind.jar (7,811,944 bytes), worldwindx.jar (3,343,413 bytes), build/worldwind.zip (119,277,694 bytes), build/doc/worldwind-javadoc.zip (16,114,354 bytes).
• passed — Built-jar runtime probe: Java 21 compiled and ran a probe against the built root jars with exact output version=NASA WorldWind Java v2.2.1, position=34.500,-117.250,1234.5, padded=3x5->4x8, probe=PASS.
• failed/blocked — GUI demo smoke: built HelloWorldWind entrypoint started, then Xvfb/JOGL display handling failed with Nativewindow X11 IOError.

Evidence was captured in this Devin session: https://app.devin.ai/sessions/36287b7c637242dba0a6a659737d5402