[General][Java SDK (Component)] serviceConfig.getRegistries() return null when destroy service , casuing NullPointerExcetpion

[mz0113]

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Apache Dubbo Component

Java SDK (apache/dubbo)

Details

serviceConfig.getRegistries() return null when destroy service ， i can`t reproduce this everytimes , it happend 2 times in 1 year .

`

private void doExport(Instance interfaceInstance, List<String> registries, BridgelessItem bridgelessItem)
        throws ClassNotFoundException, ExecutionException, InterruptedException, TimeoutException {
    ClassLoader interfaceClassLoader = bridgelessItem.getClassLoader();
    Map<String, String> interfaceInstanceMetadata = interfaceInstance.getMetadata();

    List<RegistryConfig> registryConfigs = getRegistryConfigs(registries);
    if (registryConfigs.size() == 0) {
        log.info("no matched zk,skip export,bridgelessItem:{},interfaceInstance:{}", bridgelessItem,
                interfaceInstance);
        return;
    }
    //protocol
    ProtocolConfig protocolConfig = getProtocolConfig();
    //service
    String anInterface = interfaceInstanceMetadata.get(Constants.INTERFACE);
    ServiceConfig serviceConfig;
    if (MobileAdapterService.class.getCanonicalName().equals(anInterface)) {
        serviceConfig = new MGSAdapterServiceConfig();
    } else {
        serviceConfig = new ServiceConfig();
    }
    serviceConfig.setRegistries(registryConfigs);
    serviceConfig.setProtocol(protocolConfig);
    serviceConfig.setInterface(anInterface);
    String version = interfaceInstanceMetadata.get(Constants.VERSION);
    serviceConfig.setVersion(version);

    // 设置权重,小于0的话说明未配置权重,使用全局默认权重
    Integer weight = bridgelessItem.getBridgelessConfig().getWeight();
    if (weight >= 0) {
        serviceConfig.setWeight(weight);
    }

    //解决dubbo3.0.10的tri协议存在group被默认填充tri的问题
    String group = interfaceInstanceMetadata.get(Constants.GROUP);
    if (Constants.PROTOCOL_TRI.equals(group)) {
        serviceConfig.setGroup("");
    } else {
        serviceConfig.setGroup(group);
    }

    String generic = interfaceInstanceMetadata.get(Constants.GENERIC);
    if (StringUtils.isNotBlank(generic)) {
        serviceConfig.setGeneric(generic);
    }

    serviceConfig.setInterfaceClassLoader(interfaceClassLoader);
    serviceConfig.setRef(DubboReferenceHelper.getRef(interfaceInstance, bridgelessItem, metaRPCHelper));

    //tag会被dubbo.provider.tag覆盖,所以需要手动fresh（）+setProviderConfig
    String timeout = interfaceInstanceMetadata.get(Constants.TIMEOUT);
    if (StringUtils.isNotBlank(timeout)) {
        serviceConfig.setTimeout(Integer.parseInt(timeout));
    }
    serviceConfig.refresh();

    //solveThreadPoolConfig(serviceConfig);
    // 解决只新增方法无效问题
    serviceConfig.setProxy("jdk");
    serviceConfig.setTag("");
    ProviderConfig providerConfig = getProviderConfig(timeout);
    serviceConfig.setProvider(providerConfig);

    // 注册服务
    serviceConfig.export();
    bridgelessItem.getServiceConfigList().add(serviceConfig);
    log.info("export success,appName:{},env:{},link:{},interface:{},version:{},group:{},serviceConfig:{}",
            bridgelessItem.getBridgelessConfig().getAppName(),
            bridgelessItem.getBridgelessConfig().getEnv(),
            bridgelessItem.getBridgelessConfig().getLink(), anInterface, version, group,
            serviceConfig);
}











    public void destroySync(BridgelessConfig bridgelessConfig, boolean retainClassLoader)
        throws IOException, InterruptedException {
    DubboProtocol dubboProtocol = DubboProtocol.getDubboProtocol(ApplicationModel.defaultModel());
    BridgelessItem bridgelessItem = bridgelessItemCache.getLocalCache(bridgelessConfig.getAppName(),
            bridgelessConfig.getEnv(), bridgelessConfig.getLink());
    List<ServiceConfig> serviceConfigList = bridgelessItem.getServiceConfigList();
    int toUnExportedSize = serviceConfigList.size();
    int countDownSize = 0;
    for (ServiceConfig serviceConfig : serviceConfigList) {
   //这里空指针了，serviceConfig.getRegistries()返回了ull
        **int size = serviceConfig.getRegistries().size();**
        countDownSize += size;
    }
    CountDownLatch countDownLatch = new CountDownLatch(countDownSize);

    //registry -> registerProviderUrl
    HashMap<Registry, URL> toRegistryMap = new HashMap<>();

    for (ServiceConfig serviceConfig : serviceConfigList) {
        try {
            destroyRegistry(toRegistryMap, serviceConfig);
        } catch (Exception e) {
            LogUtil.error(log, "error when destroyRegistry:{}", () -> e);
        }
    }
    //留出一点时间，用于受理C端残余的流量（zk异步通知有时延）
    TimeUnit.MILLISECONDS.sleep(unRegistryAhead);
    for (ServiceConfig serviceConfig : serviceConfigList) {
        try {
            serviceConfig.unexport();
        } catch (Exception e) {
            LogUtil.error(log, "exception when unExport,serviceConfig:{},e:", () -> serviceConfig, () -> e);
            //防止死锁
            countDownLatch.countDown();
        }

        ModuleModel scopeModel = serviceConfig.getScopeModel();
        String path = serviceConfig.getPath();
        if (StringUtils.isBlank(path)) {
            path = serviceConfig.getInterface();
        }
        String version = serviceConfig.getVersion();
        String group = serviceConfig.getGroup();
        String serviceKey = BaseServiceMetadata.buildServiceKey(path, version, group);
        //同步unexport走完后才放入，让异步unexport后去countDown
        BridgelessItemCache.setCountDownLatch2Cache(scopeModel, serviceKey, countDownLatch);
    }
    //countdown的替代方案
    //        TimeUnit.MILLISECONDS.sleep(unExportDelay);
    LogUtil.debug(log, "before await");
    countDownLatch.await(unExportDelay, TimeUnit.MILLISECONDS);
    LogUtil.debug(log, "exporters:{}", () -> dubboProtocol.getExporters().size());

    if (retainClassLoader) {//保留classLoader，以便于下次复用
        bridgelessItem.setBridgelessConfig(null);
        bridgelessItem.getServiceConfigList().clear();
    } else {
        Set<Class> interfaceSet = serviceConfigList.stream().map(serviceConfig -> serviceConfig.getInterfaceClass())
                .collect(Collectors.toSet());
        bridgelessItemCache.deleteLocalCache(bridgelessConfig.getAppName(), bridgelessConfig.getEnv(),
                bridgelessConfig.getLink());
        //dubbo中unExport时没有删除缓存,这里补删,否则由于dubbo缓存中不考虑classLoader隔离导致调用失败
        pojoUtilsExpandUtil.deleteDubboPojoUtilCache(interfaceSet, bridgelessItem.getClassLoader());
    }

    //如果原本需要unExport的服务个数大于0，则输出一下日志
    if (toUnExportedSize > 0) {
        log.info("unExport success,appName:{},env:{},link:{}", bridgelessConfig.getAppName(),
                bridgelessConfig.getEnv(), bridgeLink);
    }
}`

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[zrlw]

try the latest version?
the cause might be same with #10610