fix(RepositoryUrl): update default value VCS_HOST

1. Update the default value for `SW360Utils.readConfig(VCS_HOSTS,"[]")`
2. Before using the static `KNOWN_VCS_HOSTS`, check if the config was
   changed and update the map if required.

Signed-off-by: Gaurav Mishra <mishra.gaurav@siemens.com>

Author: GMishx

backend/common/src/main/java/org/eclipse/sw360/common/utils/RepositoryURL.java

@@ -25,14 +25,20 @@
 public class RepositoryURL {
     private static final Logger log = LogManager.getLogger(RepositoryURL.class);
     private static final String SCHEMA_PATTERN = ".+://(\\w*(?:[\\-@.\\\\s,_:/][/(.\\-)A-Za-z0-9]+)*)";
-    private static final String VCS_HOSTS_STRING = SW360Utils.readConfig(VCS_HOSTS,"");
-    private static final Map<String, String> KNOWN_VCS_HOSTS = parseVCSHosts(VCS_HOSTS_STRING);
+    private static String VCS_HOSTS_STRING = SW360Utils.readConfig(VCS_HOSTS,"[]");
+    private static Map<String, String> KNOWN_VCS_HOSTS = parseVCSHosts(VCS_HOSTS_STRING);
 
     public String processURL(String url) {
         return sanitizeVCS(url);
     }
 
     private static String formatVCSUrl(String host, String[] urlParts) {
+        if (VCS_HOSTS_STRING != null &&
+                !VCS_HOSTS_STRING.equals(SW360Utils.readConfig(VCS_HOSTS, "[]"))) {
+            // Config has updated, update the cache
+            VCS_HOSTS_STRING = SW360Utils.readConfig(VCS_HOSTS,"[]");
+            KNOWN_VCS_HOSTS = parseVCSHosts(VCS_HOSTS_STRING);
+        }
         String formatString = KNOWN_VCS_HOSTS.get(host);
 
         int paramCount = formatString.split("%s", -1).length - 1;