java module_error ai_generated partial

WARNING: An illegal reflective access operation has occurred

ID: java/illegal-reflective-access-warning

Also available as: JSON · Markdown · 中文
80%Fix Rate
88%Confidence
1Evidence
2023-07-20First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
Java 9 active — — —
Java 11 active — — —
Java 17 active — — —
Java 21 active — — —

Root Cause

Code is using reflection to access a member of a class in a module that does not export the package to the caller, which is disallowed by the Java module system (JPMS) since Java 9.

generic

中文

代码使用反射访问某个模块中类的成员，但该模块未将包导出给调用者，自 Java 9 起，Java 模块系统（JPMS）禁止此操作。

Official Documentation

https://docs.oracle.com/en/java/javase/17/migrate/migration-guide.pdf

Workarounds

  1. 90% success Add JVM args to open the specific package: `--add-opens java.base/java.lang=ALL-UNNAMED` (replace package and module as needed). 
    Add JVM args to open the specific package: `--add-opens java.base/java.lang=ALL-UNNAMED` (replace package and module as needed).
  2. 85% success Update the library to a version that uses proper module exports or uses `ModuleLayer` API to access non-exported packages. 
    Update the library to a version that uses proper module exports or uses `ModuleLayer` API to access non-exported packages.
  3. 95% success If you control the library, add `exports` directive in `module-info.java` to export the package to the caller module. 
    If you control the library, add `exports` directive in `module-info.java` to export the package to the caller module.

中文步骤

  1. 添加 JVM 参数以打开特定包：`--add-opens java.base/java.lang=ALL-UNNAMED`（根据需要替换模块和包）。
  2. 将库更新到使用正确模块导出或使用 `ModuleLayer` API 访问非导出包的版本。
  3. 如果你控制库，在 `module-info.java` 中添加 `exports` 指令，将包导出给调用者模块。

Dead Ends

Common approaches that don't work:

  1. Add `--illegal-access=permit` JVM flag to allow all reflective access. 95% fail

    The `--illegal-access=permit` flag was removed in Java 17; it only works in Java 9-16. In Java 17+, it causes an error: 'Java.lang.IllegalArgumentException: IllegalAccessError'.

  2. Set `AccessibleObject.setAccessible(true)` to bypass the warning. 80% fail

    The warning is generated by the JVM's reflective access check; setAccessible does not suppress the warning or fix the underlying module access issue.

  3. Ignore the warning; it's just a warning. 70% fail

    In future Java versions, illegal reflective access will throw an `InaccessibleObjectException` at runtime, breaking the application.