String.join is an easy-to-use utility method in String class.
public class StringJoin{
public static void main(String args[]){
//The first argument (refered as joinString) is used to join the subsequent argument(s)
String finalString = String.join("-","String","join","example"," Hyphen(-) used to join");
System.out.println("Output 1: " + finalString);
//In case there is only 1 argument after the first argument, then the second argument is not appended with the joinString
finalString = String.join("-","String");
System.out.println("Output 2: " + finalString);
}
}