Best way to convert list to comma separated string in java

I have Set<String> result & would like to convert it to comma separated string. My approach would be as shown below, but looking for other opinion as well.

List<String> slist = new ArrayList<String> (result);
StringBuilder rString = new StringBuilder();

Separator sep = new Separator(", ");
//String sep = ", ";
for (String each : slist) {
    rString.append(sep).append(each);
}

return rString;

Since Java 8:

String.join(",", slist);

From Apache Commons library:

import org.apache.commons.lang3.StringUtils

Use:

StringUtils.join(slist, ',');

Another similar question and answer here

You could count the total length of the string first, and pass it to the StringBuilder constructor. And you do not need to convert the Set first.

Set<String> abc = new HashSet<String>();
abc.add("A");
abc.add("B");
abc.add("C");

String separator = ", ";
int total = abc.size() * separator.length();
for (String s : abc) {
	total += s.length();
}

StringBuilder sb = new StringBuilder(total);
for (String s : abc) {
	sb.append(separator).append(s);
}

String result = sb.substring(separator.length()); // remove leading separator

The Separator you are using is a UI component. You would be better using a simple String sep = ", ".