Java: how to use a loop to create a string without printing?

Question

I'm a beginner with java and one concept is rather unclear to me. I need to create a method that creates a new string by replicating another string. For example, if the String1 is "java" and it is specified that it needs to be repeated 4 times and each of them needs to be separated with a comma, the new string would look like this: java, java, java, java

However, the method should not print it, but only create a new string that is then printed in the main program. This is a problem for me, because I have trouble understanding, how can I use a loop to create something without printing it. I think that the following code would print it correctly:

public static void replicate(String str, int times) {
   for (int i = 0; i < times; i++) {
      System.out.print(str);
      if (i < times -1) {
         System.out.print(", ");
      }
   }
}

How could I transform it so that I could use the method to create a new string without printing it? I am assuming this is something super simple, but I just don't know at all how to do this, because every guide just uses examples of printing in these kinds of situations.

Answer 1

This is much better with Collections and join

import java.util.*;
public class Main 
{
    public static void main(String[] args) 
    {


        String newstr=String.join(",", Collections.nCopies(3, "java"));
        System.out.println(newstr);
    }
}

Working fiddle-https://repl.it/repls/OfficialInvolvedObject

Answer 2

The following code should be useful for academic purposes in which you cannot use all of Java's libraries. You want to use a variable to store the repeated text and then return that variable to the main method for it to be printed. For non academic purposes or in cases when efficiency is a priority the java.lang.StringBuilder object should be used.

 public static String replicate(String str, int times) {
    String newString = "";
    for (int i = 0; i < times; i++) {
        newString = newString + str;
        if(i<times-1){
            newString = newString + ", ";
        }
    }
    return newString;
}