For v2.8.3 the following should work:

YAMLFactory yf = new YAMLFactory(); ObjectMapper mapper = new ObjectMapper(yf); ObjectNode root = (ObjectNode) mapper.readTree(yamlFileIn); // modify root here
FileOutputStream fos = new FileOutputStream(yamlFileOut); SequenceWriter sw = mapper.writerWithDefaultPrettyPrinter().writeValues(fos); sw.write(root);