Here are my object mapper and yml formatter:

public static final YAMLFactory YML_FORMATTER = new YAMLFactory()
          .enable(YAMLGenerator.Feature.MINIMIZE_QUOTES)
          .disable(YAMLGenerator.Feature.ALWAYS_QUOTE_NUMBERS_AS_STRINGS);

ObjectMapper mapperForYml = new ObjectMapper(YML_FORMATTER);

I write object to a file as:

try (FileOutputStream fos = new FileOutputStream("C:/Users/somepath/file.yml")) {
    fos.write(mapperForYml.writeValueAsBytes(bean));
} catch (IOException e) {
    throw new RuntimeException(e);
}

The bean has getters and setters added.
I added enable(YAMLGenerator.Feature.MINIMIZE_QUOTES) above because I don’t was quotes in my file like json.

I have a field in my pojo/bean of type String which may have numeric value. When the value is numeric, I want that value to be written in yml file with single quotes.

Example (expected output):

group:
  member:
    name: John Doe
    location: US
    pcId: '23451'

I tried to append quotes using multiple ways like:

if (org.apache.commons.lang3.StringUtils.isNumeric(bean.getPcId())) {
      me.setValue(StringUtils.quote(bean.getPcId()));
}

But doing this, I get result as '''7657658''' in yml file (extra quotes added).

Tried traditional String concatenation, got same result with extra quotes.
Also tried:

java.util.regex.Pattern.quote(bean.getPcId());   // result: /Q7657658/E

I cannot make field in pojo Integer or Long.