浅谈MyBatis-Plus 提示发生了非法的反射访问操作

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.baomidou.mybatisplus.core.toolkit.SetAccessibleAction (file:/C:/Users/wangbo.GTCOM/.m2/repository/com/baomidou/mybatis-plus-core/3.4.3.4/mybatis-plus-core-3.4.3.4.jar) to field java.lang.invoke.SerializedLambda.capturingClass
WARNING: Please consider reporting this to the maintainers of com.baomidou.mybatisplus.core.toolkit.SetAccessibleAction
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

import java.lang.reflect.Field;
import java.util.ArrayList;

public class TestReflect {

    public static int getCapacity(ArrayList<?> l) throws Exception {
        Field dataField = l.getClass().getDeclaredField("elementData");
        // 即使设置了可访问也会触发警告
        dataField.setAccessible(true);
        // 注意这行
        return ((Object[]) dataField.get(l)).length;
    }

    public static void main(String[] args) {
        var arr = new ArrayList<Integer>(4);
        try {
            System.out.println("capacity:" + TestReflect.getCapacity(arr));        
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by TestReflect (file:/tmp/TestReflect.java) to field java.util.ArrayList.elementData
WARNING: Please consider reporting this to the maintainers of TestReflect
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
capacity:4

$ java --illegal-access=warn TestReflect.java

WARNING: Illegal reflective access by TestReflect (file:/tmp/TestReflect.java) to field java.util.ArrayList.elementData
capacity:4

$ java --illegal-access=deny TestReflect.java

java.lang.reflect.InaccessibleObjectException: Unable to make field transient java.lang.Object[] java.util.ArrayList.elementData accessible: module java.base does not "opens java.util" to unnamed module @72967906
        at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:349)
        at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:289)
        at java.base/java.lang.reflect.Field.checkCanSetAccessible(Field.java:174)
        at java.base/java.lang.reflect.Field.setAccessible(Field.java:168)
        at TestReflect.getCapacity(TestReflect.java:7)
        at TestReflect.main(TestReflect.java:14)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:564)
        at jdk.compiler/com.sun.tools.javac.launcher.Main.execute(Main.java:415)
        at jdk.compiler/com.sun.tools.javac.launcher.Main.run(Main.java:192)
        at jdk.compiler/com.sun.tools.javac.launcher.Main.main(Main.java:132)

$ java --add-opens java.base/java.util=ALL-UNNAMED TestReflect.java

capacity:4