sentinel运行报错问题处理:Unable to make protected final java.lang.Class java.lang.ClassLoader.define

使用命令：java -jar sentinel-dashboard-1.8.3.jar启动后异常情况如下

java.lang.IllegalStateException: Cannot load configuration class: com.alibaba.csp.sentinel.dashboard.DashboardApplication
        at org.springframework.context.annotation.ConfigurationClassPostProcessor.enhanceConfigurationClasses(ConfigurationClassPostProcessor.java:414) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanFactory(ConfigurationClassPostProcessor.java:254) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:282) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:126) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:694) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:532) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:333) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1277) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1265) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
        at com.alibaba.csp.sentinel.dashboard.DashboardApplication.main(DashboardApplication.java:33) ~[classes!/:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) ~[sentinel-dashboard-1.8.3.jar:na]
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) ~[sentinel-dashboard-1.8.3.jar:na]
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) ~[sentinel-dashboard-1.8.3.jar:na]
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) ~[sentinel-dashboard-1.8.3.jar:na]
Caused by: java.lang.ExceptionInInitializerError: null
        at org.springframework.context.annotation.ConfigurationClassEnhancer.newEnhancer(ConfigurationClassEnhancer.java:122) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.context.annotation.ConfigurationClassEnhancer.enhance(ConfigurationClassEnhancer.java:110) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.context.annotation.ConfigurationClassPostProcessor.enhanceConfigurationClasses(ConfigurationClassPostProcessor.java:403) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        ... 20 common frames omitted
Caused by: org.springframework.cglib.core.CodeGenerationException: java.lang.reflect.InaccessibleObjectException-->Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module @812f2fb
        at org.springframework.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:464) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:336) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:93) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:91) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
        at org.springframework.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.internal.LoadingCache.get(LoadingCache.java:34) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:116) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:291) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.KeyFactory$Generator.create(KeyFactory.java:221) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.KeyFactory.create(KeyFactory.java:174) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.KeyFactory.create(KeyFactory.java:153) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.proxy.Enhancer.<clinit>(Enhancer.java:73) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        ... 23 common frames omitted
Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module @812f2fb
        at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:354) ~[na:na]
        at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:297) ~[na:na]
        at java.base/java.lang.reflect.Method.checkCanSetAccessible(Method.java:199) ~[na:na]
        at java.base/java.lang.reflect.Method.setAccessible(Method.java:193) ~[na:na]
        at org.springframework.cglib.core.ReflectUtils$1.run(ReflectUtils.java:61) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:569) ~[na:na]
        at org.springframework.cglib.core.ReflectUtils.<clinit>(ReflectUtils.java:52) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.KeyFactory$Generator.generateClass(KeyFactory.java:243) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:25) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        at org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:329) ~[spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
        ... 35 common frames omitted

2022-10-21 01:04:56.089  INFO 1487 --- [           main] ConfigServletWebServerApplicationContext : Closing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@4bec1f0c: startup date [Fri Oct 21 01:04:55 CST 2022]; root of context hierarchy

解决方法
更改启动命令，打开特定的包装进行反射：
java --add-opens java.base/java.lang=ALL-UNNAMED -jar sentinel-dashboard-1.8.1.jar

注：我的电脑环境装的是jdk17，版本较高，由于 JDK 8 中有关反射相关的功能自从 JDK 9 开始就已经被限制了。
为了兼容原先的版本，需要在运行项目时添加 --add-opens java.base/java.lang=ALL-UNNAMED 选项来开启这种默认不被允许的行为。