Best way to concatenate List of String objects? [duplicate]

Answer 1

A variation on codefin's answer

public static String concatStringsWSep(Iterable strings, String separator) {
    StringBuilder sb = new StringBuilder();
    String sep = "";
    for(String s: strings) {
        sb.append(sep).append(s);
        sep = separator;
    }
    return sb.toString();                           
}