com.alibaba.dubbo.governance.web.governance.module.screen.Providers#getServiceAppMap 
at line 133 ， should be providers.size > 0 or just delete this comparison cause the next for will skip if proviers.size == 0
providers = providerService.findByService(service);
            value = service + separators + request.getRequestURI();
        }
        
        else if (address != null && address.length() > 0) {
            providers = providerService.findByAddress(address);
            value = address + separators + request.getRequestURI();
        }
        
        else if (application != null && application.length() > 0) {
            providers = providerService.findByApplication(application);
            value = application + separators + request.getRequestURI();
        }
        
        else {
            providers = providerService.findAll();
        }
        context.put("providers", providers);
        context.put("serviceAppMap", getServiceAppMap(providers));
        
        setSearchHistroy(context, value);
    }
    /**
     *
     * Calculate the application list corresponding to each service, to facilitate the "repeat" prompt on service page
     * @param providers app services
     */
    private Map<String, Set<String>> getServiceAppMap(List<Provider> providers) {
        Map<String, Set<String>> serviceAppMap = new HashMap<String, Set<String>>();
        if (providers != null && providers.size() >= 0) {