Implement CDC 1.1 LinkedHashMap

[dlunch]

Summary

• add the CDC 1.1 java.util.LinkedHashMap public API
• preserve insertion or access order across map views with live fail-fast iterators
• support map copies, rehashing, null mappings, iterator removal, and removeEldestEntry policies
• extend HashMap with load-factor handling, modification tracking, and internal subclass hooks
• document that Java compatibility work must use public specifications, Javadocs, and observable behavior rather than runtime implementation source

Validation

• cargo fmt --all -- --check
• git diff --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test -p java_runtime (468 passed)
• cargo test --workspace (531 passed, 1 existing ignored)

[codecov]

Codecov Report

❌ Patch coverage is 97.31903% with 20 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.74%. Comparing base (c92a32a) to head (bd46e1e).

Files with missing lines	Patch %	Lines
...a_runtime/src/classes/java/util/linked_hash_map.rs	93.63%	17 Missing ⚠️
.../java/util/linked_hash_map_linked_hash_iterator.rs	96.38%	3 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## main #197 +/- ##
==========================================
+ Coverage 87.57% 87.74% +0.17% 
==========================================
Files 292 298 +6 Lines 38347 39025 +678 ==========================================
+ Hits 33582 34244 +662 - Misses 4765 4781 +16 

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[Copilot]

Pull request overview

This PR adds a CDC 1.1-compatible java.util.LinkedHashMap implementation to java_runtime, including ordered views and fail-fast iterators, and refactors HashMap to provide internal hooks (load factor, mod tracking, entry lifecycle callbacks) that LinkedHashMap builds on.

Changes:

• Introduce java/util/LinkedHashMap plus ordered entry nodes and iterator types (key/value/entry) backed by a linked-list header sentinel.
• Extend java/util/HashMap with load-factor support, modCount, and virtual hooks (initializeMap, storeNewEntry, insertNewEntry, keyIterator/valueIterator/entryIterator, onAccess/onRemoval) to support subclass behaviors.
• Add comprehensive runtime-level tests validating constructor argument validation, insertion/access order semantics, view/iterator behavior (including fail-fast), rehashing, and removeEldestEntry.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
java_runtime/tests/classes/java/util/test_linked_hash_map.rs	Adds behavior and API-shape tests for CDC 1.1 LinkedHashMap, including order semantics, null mappings, rehashing, iterators, and removeEldestEntry.
java_runtime/tests/classes/java/util/mod.rs	Registers the new LinkedHashMap test module.
java_runtime/src/loader.rs	Registers LinkedHashMap and its nested runtime classes in the class proto loader.
java_runtime/src/classes/java/util/linked_hash_map.rs	Implements java/util/LinkedHashMap constructors, order-preserving storage, access-order get, and iterator factories.
java_runtime/src/classes/java/util/linked_hash_map_entry.rs	Implements ordered entry nodes and access/removal hooks to maintain the linked list and fail-fast behavior.
java_runtime/src/classes/java/util/linked_hash_map_linked_hash_iterator.rs	Implements the shared ordered, fail-fast iterator base for LinkedHashMap views.
java_runtime/src/classes/java/util/linked_hash_map_key_iterator.rs	Key iterator specialization over ordered entries.
java_runtime/src/classes/java/util/linked_hash_map_value_iterator.rs	Value iterator specialization over ordered entries.
java_runtime/src/classes/java/util/linked_hash_map_entry_iterator.rs	Entry iterator specialization returning Map.Entry objects.
java_runtime/src/classes/java/util/hash_map.rs	Refactors HashMap to add load factor, modCount, subclass hooks, and iterator indirection for ordered/fail-fast subclasses.
java_runtime/src/classes/java/util/hash_map_values.rs	Updates Values view iteration/removal to use entryIterator/valueIterator hooks.
java_runtime/src/classes/java/util/hash_map_key_set.rs	Updates KeySet iterator to use the keyIterator hook.
java_runtime/src/classes/java/util/hash_map_entry_set.rs	Updates EntrySet iterator to use the entryIterator hook.
java_runtime/src/classes/java/util/hash_map_entry.rs	Adds entry lifecycle hooks (onAccess, onRemoval) and ensures public accessors align with public API usage.
java_runtime/src/classes/java/util.rs	Wires new util module files into the build and re-exports the new types.
AGENTS.md	Documents compatibility/provenance guidance for Java compatibility work.

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