In this short post, we’d explain how to convert/ reduce a List of Strings into a single comma (,) separated String using Java-8 Streams API. here’s the code: import java.util.Arrays; import java.util.List; public class ListToString { public static String getCommaSeparatedString(List<string> input) { return input.stream() .reduce( // identity function for String concatenation "", (s1, s2) -> ...