output: #fixed code
                                  private void checkLocalConfig(CacheData cacheData) {
          final String dataId = cacheData.dataId;
          final String group = cacheData.group;
          final String tenant = cacheData.tenant;
          File path = LocalConfigInfoProcessor.getFailoverFile(agent.getName(), dataId, group, tenant);
  
          // 没有 -> 有
          if (!cacheData.isUseLocalConfigInfo() && path.exists()) {
              String content = LocalConfigInfoProcessor.getFailover(agent.getName(), dataId, group, tenant);
              String md5 = MD5Utils.md5Hex(content, Constants.ENCODE);
              cacheData.setUseLocalConfigInfo(true);
              cacheData.setLocalConfigInfoVersion(path.lastModified());
              cacheData.setContent(content);
  
              LOGGER.warn("[{}] [failover-change] failover file created. dataId={}, group={}, tenant={}, md5={}, content={}",
                  agent.getName(), dataId, group, tenant, md5, ContentUtils.truncateContent(content));
              return;
          }
  
          // 有 -> 没有。不通知业务监听器，从server拿到配置后通知。
          if (cacheData.isUseLocalConfigInfo() && !path.exists()) {
              cacheData.setUseLocalConfigInfo(false);
              LOGGER.warn("[{}] [failover-change] failover file deleted. dataId={}, group={}, tenant={}", agent.getName(),
                  dataId, group, tenant);
              return;
          }
  
          // 有变更
          if (cacheData.isUseLocalConfigInfo() && path.exists()
              && cacheData.getLocalConfigInfoVersion() != path.lastModified()) {
              String content = LocalConfigInfoProcessor.getFailover(agent.getName(), dataId, group, tenant);
              String md5 = MD5Utils.md5Hex(content, Constants.ENCODE);
              cacheData.setUseLocalConfigInfo(true);
              cacheData.setLocalConfigInfoVersion(path.lastModified());
              cacheData.setContent(content);
              LOGGER.warn("[{}] [failover-change] failover file changed. dataId={}, group={}, tenant={}, md5={}, content={}",
                  agent.getName(), dataId, group, tenant, md5, ContentUtils.truncateContent(content));
          }
      }
input: #vulnerable code 
                                  private void checkLocalConfig(CacheData cacheData) {
          final String dataId = cacheData.dataId;
          final String group = cacheData.group;
          final String tenant = cacheData.tenant;
          File path = LocalConfigInfoProcessor.getFailoverFile(agent.getName(), dataId, group, tenant);
  
          // 没有 -> 有
          if (!cacheData.isUseLocalConfigInfo() && path.exists()) {
              String content = LocalConfigInfoProcessor.getFailover(agent.getName(), dataId, group, tenant);
              String md5 = MD5.getInstance().getMD5String(content);
              cacheData.setUseLocalConfigInfo(true);
              cacheData.setLocalConfigInfoVersion(path.lastModified());
              cacheData.setContent(content);
  
              LOGGER.warn("[{}] [failover-change] failover file created. dataId={}, group={}, tenant={}, md5={}, content={}",
                  agent.getName(), dataId, group, tenant, md5, ContentUtils.truncateContent(content));
              return;
          }
  
          // 有 -> 没有。不通知业务监听器，从server拿到配置后通知。
          if (cacheData.isUseLocalConfigInfo() && !path.exists()) {
              cacheData.setUseLocalConfigInfo(false);
              LOGGER.warn("[{}] [failover-change] failover file deleted. dataId={}, group={}, tenant={}", agent.getName(),
                  dataId, group, tenant);
              return;
          }
  
          // 有变更
          if (cacheData.isUseLocalConfigInfo() && path.exists()
              && cacheData.getLocalConfigInfoVersion() != path.lastModified()) {
              String content = LocalConfigInfoProcessor.getFailover(agent.getName(), dataId, group, tenant);
              String md5 = MD5.getInstance().getMD5String(content);
              cacheData.setUseLocalConfigInfo(true);
              cacheData.setLocalConfigInfoVersion(path.lastModified());
              cacheData.setContent(content);
              LOGGER.warn("[{}] [failover-change] failover file changed. dataId={}, group={}, tenant={}, md5={}, content={}",
                  agent.getName(), dataId, group, tenant, md5, ContentUtils.truncateContent(content));
          }
      } 
                              #location 10 
                              #vulnerability type NULL_DEREFERENCE