Exception subclasses are supposed to have a serial number

This warning in Eclipse tells me so:

"The serializable class UpdateException does not declare a static final
serialVersionUID field of type long"

src/org/fdroid/fdroid/updater/RepoUpdater.java

@@ -268,6 +268,7 @@ abstract public class RepoUpdater {
 
     public static class UpdateException extends Exception {
 
+        private static final long serialVersionUID = -4492452418826132803L;
         public final Repo repo;
 
         public UpdateException(Repo repo, String message) {