Map<ModificationKind, List<ASTModification>> map = classifiedModifications.get(node);
if (map == null) {
map = new TreeMap<ModificationKind, List<ASTModification>>();
classifiedModifications.put(node, map);
}
final ModificationKind kind = modification.getKind();
List<ASTModification> list = map.get(kind);
if (list == null) {
list = new ArrayList<ASTModification>(2);
map.put(kind, list);
}