eclipse - xxSkin 类中的深度反射失败

Question

自更新 9-u175 以来，java 默认允许非法访问，因此允许所有旧的反射技巧。工作正常，除非涉及到 control.skin 中的类(可能还有其他类，没有检查) - 要重现，运行下面的示例，单击按钮并查看访问如何成功，直到尝试访问私有(private)的行ButtonSkin 中的字段。堆栈跟踪:

Exception in thread "JavaFX Application Thread" java.lang.reflect.InaccessibleObjectException: 
Unable to make field private final com.sun.javafx.scene.control.behavior.BehaviorBase javafx.scene.control.skin.ButtonSkin.behavior accessible: 
module javafx.controls does not "opens javafx.scene.control.skin" to unnamed module @537fb2
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:337)
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:281)
    at java.base/java.lang.reflect.Field.checkCanSetAccessible(Field.java:176)
    at java.base/java.lang.reflect.Field.setAccessible(Field.java:170)

我的上下文:jdk9-u175, eclipse-oxygen-R with patch for java9, 项目中的访问规则设置为允许 javafx/**

问题是:谁是罪魁祸首？ FX、Eclipse、EA 还是 ..？

这个例子:

import java.lang.reflect.Field;
import java.util.logging.Logger;

import javafx.application.Application;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.SkinBase;
import javafx.scene.control.skin.ButtonSkin;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
import com.sun.javafx.scene.control.LambdaMultiplePropertyChangeListenerHandler;

public class AccessFieldFX extends Application {

    private Parent getContent() {
        Button button = new Button("something to click on");
        // okay
        Object def = invokeGetFieldValue(Button.class, button, "defaultButton");

        button.setOnAction(e -> {
            ButtonSkin skin = (ButtonSkin) button.getSkin();
            // okay
            LambdaMultiplePropertyChangeListenerHandler cl =
                    (LambdaMultiplePropertyChangeListenerHandler) invokeGetFieldValue(SkinBase.class, skin, "lambdaChangeListenerHandler");
            // okay
            Object clField = invokeGetFieldValue(LambdaMultiplePropertyChangeListenerHandler.class, cl, "EMPTY_CONSUMER");
            // failure
            Object beh = invokeGetFieldValue(ButtonSkin.class, skin, "behavior");
        });
        BorderPane pane = new BorderPane(button);
        return pane;
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setScene(new Scene(getContent(), 600, 400));
//        primaryStage.setTitle(FXUtils.version());
        primaryStage.show();
    }

    public static Object invokeGetFieldValue(Class declaringClass, Object target, String name) {
        try {
            Field field = declaringClass.getDeclaredField(name);
            field.setAccessible(true);
            return field.get(target);
        } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static void main(String[] args) {
        launch(args);
    }

    @SuppressWarnings("unused")
    private static final Logger LOG = Logger
            .getLogger(AccessFieldFX.class.getName());
}

Answer 1

为了防止对新 API 的意外依赖，非法访问仅授予 Java 9 之前存在的包 - 因此我假设 com.sun.javafx.scene.control.behavior是新的。

在他的mail with the revised proposal for --illegal-access Mark Reinhold 写道(强调我的):

--illegal-access=permit

This mode opens each package in each module in the run-time image to code in all unnamed modules, i.e., code on the class path, if that package existed in JDK 8. This enables both static access, i.e., by compiled bytecode, and deep reflective access, via the platform's various reflection APIs.

The first reflective-access operation to any such package causes a warning to be issued, but no warnings are issued after that point. This single warning describes how to enable further warnings.

This mode will be the default for JDK 9. It will be removed in a future release.