Fixed: A default fulfils requirement, but does not count as assignment.

src/main/java/com/beust/jcommander/JCommander.java

@@ -858,7 +858,6 @@ else if (commands.isEmpty()) {
             // but the one assigned on the variable initialization), make it as assigned and
             // remove it from the list of parameters to be required
             if (parameterDescription.getDefault() != null && !parameterDescription.getParameterized().getType().isPrimitive()) {
-                fields.get(parameterDescription.getParameterized()).setAssigned(true);
                 requiredFields.remove(parameterDescription.getParameterized());
             }
         }