Snake yaml : Issue with duplicate keys in Yaml template

I have a Yaml template which needs to be updated dynamically.

I am reading Yaml template using snake yaml and updating it with dynamic content and generating new yaml file with new values

I am following below steps to update yaml file.

1. Assume below is the Yaml template

--------------------------------
version: snapshot-01
kind: sample
metadata:
  name: abc
options: "<placeholder>"
--------------------------------

I am converting yaml into Map using snake yaml as shown below

 Yaml yaml = new Yaml();
 InputStream inputStream = 
 this.getClass().getClassLoader().getResourceAsStream(yamlTemplateLocation);
 Map<String, Object>yamlMap = yaml.load(inputStream); 

I am replacing the required fields dynamically as shown below.

yamlMap.put("version","v-1.0");
yamlMap.put("options","newOptions");

And finally I am converting map to String and strore as Yaml file using below code :

DumperOptions options = new DumperOptions();
options.setSplitLines(false);
Yaml yaml = new Yaml(options);
System.out.println(yaml.dump(yamlMap));

Generated yaml file is :

version: "v-1.0"
kind: sample
metadata:
  name: abc
options:  "newOptions"
--------------------------------

I got some issue now

The template needs to be changed as below

--------------------------------
version: snapshot-01
kind: sample
metadata:
  name: abc
options: "<placeholder>"
---
version: v2
kind: sample
metadata:
 type: <abc> 
--------------------------------

I have to include some extra piece in the template which includes three dashes and also same same keys like version, kind and metadata

Now I need to update template with new values as shown below

version: "v-1.0"
kind: sample
metadata:
  name: abc
options:  "newOptions"
---
version: v2-0
kind: sample
metadata:
 type: "newType"

My question is --> I am converting yaml to map to update. So how can I handle if there are duplicate keys in yaml (like version, version) in the above example.

Could anyone please help me with this? Thanks in advance!

Three dashes mark the end of the YAML document and the begin of a new document in this case, meaning you have multiple YAML documents in a single file. In that case, you need to use loadAll to load all documents, and then dumpAll to write a file with multiple documents:

List<Object> output = new ArrayList<Object>();
boolean first = true;
for (Map<String, Object> doc : yaml.loadAll(inputStream)) {
  if (first) {
    doc.put("version","v-1.0");
    doc.put("options","newOptions");
    first = false;
  }
  output.add(doc);
}
System.out.println(yaml.dumpAll(output));

You won't have problems with duplicate keys because they are in different documents.