private void checkNoAbstractMethodsNonabstractClass(ClassNode node) {
   if (isAbstract(node.getModifiers())) return;
   List<MethodNode> abstractMethods = node.getAbstractMethods();
   if (abstractMethods == null) return;
   for (MethodNode method : abstractMethods) {
     addError(
         "Can't have an abstract method in a non-abstract class."
             + " The "
             + getDescription(node)
             + " must be declared abstract or"
             + " the "
             + getDescription(method)
             + " must be implemented.",
         node);
   }
 }