WARNING: Illegal reflective access by com.google.inject.assistedinject.FactoryProvider2

I’m seeing this warning when starting Gerrit with Java11:

$ java -jar bazel-bin/release.war init -d ../test_site_gerrit_3.2 --batch --dev
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.google.inject.assistedinject.FactoryProvider2 (file:/home/davido/.gerritcodereview/tmp/gerrit_6966619352392581698_app/guice-assistedinject-4.2.3.jar) to constructor java.lang.invoke.MethodHandles$Lookup(java.lang.Class,int)
WARNING: Please consider reporting this to the maintainers of com.google.inject.assistedinject.FactoryProvider2
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

The code has even “this isn’t a public API” comment:

https://github.com/google/guice/blob/master/extensions/assistedinject/src/com/google/inject/assistedinject/FactoryProvider2.java#L900-L915

// Note: this isn't a public API, but we need to use it in order to call default methods on (or
  // with) non-public types.  If it doesn't exist, the code falls back to a less precise check.
  private static final Constructor<MethodHandles.Lookup> methodHandlesLookupCxtor =
      findMethodHandlesLookupCxtor();

  private static Constructor<MethodHandles.Lookup> findMethodHandlesLookupCxtor() {
    try {
      Constructor<MethodHandles.Lookup> cxtor =
          MethodHandles.Lookup.class.getDeclaredConstructor(Class.class, int.class);
      cxtor.setAccessible(true);
      return cxtor;
    } catch (ReflectiveOperationException ignored) {
      // Ignore, the code falls back to a less-precise check if we can't create method handles.
      return null;
    }
  }

See also this upstream issue: [1].

[1] https://crbug.com/gerrit/12639

[ogregoire]

I was kind of hoping this would be fixed by 5.0.0-BETA-1, but nope, it’s still there.

[davido]

Encountered this issue while initializing Gerrit 3.3.1 using JDK 12.0.1. Looks like the issue isn’t fixed

Correct.