parser/java: output instability

**Describe the bug**

The java parser generates different outputs for the same input.

**To Reproduce**

1. clone main branch and build abcoder
2. run abcoder on testdata/java/4_full_maven_repo twice
3. compare the generated uniasts (using the smart diff script)

**Expected behavior**

For the same repo, abcoder should generate two identical uniASTs.

**Screenshots**

```bash
[~/Programs/test/arti/java/abcoder] [main =] [05:43:56 PM] zhenyang
$ git status
On branch main
Your branch is up to date with 'origin/main'.

nothing to commit, working tree clean

[~/Programs/test/arti/java/abcoder] [main =] [05:43:57 PM] zhenyang
$ go build

[~/Programs/test/arti/java/abcoder] [main =] [05:44:02 PM] zhenyang
$ ./abcoder parse java testdata/java/4_full_maven_repo -o java_1.json
2025/09/26 17:44:13 Using JDTLS_ROOT_PATH from environment: /home/zhenyang/O/data/Programs/bytedance/LanguageServers
[ERROR]17:44:13 client.go:264: LSP server stderr: OpenJDK 64-Bit Server VM warning: Options -Xverify:none and -noverify were deprecated in JDK 13 and will likely be removed in a future release.
[ERROR]17:44:14 client.go:264: LSP server stderr: Sep 26, 2025 5:44:14 PM org.apache.aries.spifly.BaseActivator log
[ERROR]17:44:14 client.go:264: LSP server stderr: INFO: Registered provider ch.qos.logback.classic.servlet.LogbackServletContainerInitializer of service jakarta.servlet.ServletContainerInitializer in bundle ch.qos.logback.classic
[ERROR]17:44:14 client.go:264: LSP server stderr: Sep 26, 2025 5:44:14 PM org.apache.aries.spifly.BaseActivator log
[ERROR]17:44:14 client.go:264: LSP server stderr: INFO: Registered provider ch.qos.logback.classic.spi.LogbackServiceProvider of service org.slf4j.spi.SLF4JServiceProvider in bundle ch.qos.logback.classic

[~/Programs/test/arti/java/abcoder] [main =] [05:44:47 PM] zhenyang
$ ./abcoder parse java testdata/java/4_full_maven_repo -o java_2.json >/dev/null 2>&1

[~/Programs/test/arti/java/abcoder] [main =] [05:45:06 PM] zhenyang
$ ./script/diffjson.py java_1.json java_2.json 2>&1 | head

Differences found between 'java_1.json' and 'java_2.json':

Value Changed at: root['Modules']['com.example.test:core-module:1.0.0-SNAPSHOT']['Packages']['com.example.core.repository']['Types']['InMemoryUserRepository']['Methods']['findAll()']['Name']
- old: 'findAll()'
+ new: 'InMemoryUserRepository.findAll()'
--------------------
Value Changed at: root['Modules']['com.example.test:core-module:1.0.0-SNAPSHOT']['Packages']['com.example.core.repository']['Types']['InMemoryUserRepository']['Methods']['save(User)']['Name']
- old: 'InMemoryUserRepository.save(User)'
+ new: 'save(User)'
--------------------
```

**Version:**

main branch

**Environment:**

The output of `go env`.

**Additional context**

Add any other context about the problem here.

abcoderをビルドし、testdata/java/4_full_maven_repoに対して2つのコマンドを実行して、出力をscript/diffjson.pyと比較します。まず、メソッド名の生成に関係するparser/javaパスを追跡し、報告されたInMemoryUserRepositoryの差分を再現可能なケースとして使用します。繰り返しパースした結果、同一のuniASTsが生成されれば完了です。

索引モデルが issue の本文から書いたものです。