public class ReflectField {    protected String test = "test string in class ReflectField!";}

/** * subclass of ReflectField * * 通过子类把父类的test字段隐藏掉，不让反射获取到其值 * 正确的应该是用java的security manager来管理 */import java.lang.reflect.Field;public class ReflectExtendsField extends ReflectField {    // protected String test = "test string in class ReflectExtendsField!";    private String test = "test string in class ReflectExtendsField!";    public static void main(String[] args) throws Exception {        // Class ref = Class.forName("ReflectExtendsField");        Class ref = ReflectExtendsField.class;        Field[] fields = ref.getFields();        System.out.println(fields.length);        for (Field field : fields) {            field.setAccessible(true);            System.out.println(field.get(ref));        }        Field testField = ref.getDeclaredField("test");        testField.setAccessible(true);        System.out.println(testField);        System.out.println(testField.get(ref));    }}