Convert a List of Strings into a single String using ArrayUtils in java

Use join

String joined2 = String.join(",", test );

You can't do this with ArrayUtils. You can use Apache's StringUtils join function to get the result you want.

// result is "one,two,three"
StringUtils.join(test, ',');

If you don't want to use a library, you can create this function:

public static String joiner(List<String> list, String separator){
    StringBuilder result = new StringBuilder();
    for(String term : list) result.append(term + separator);
    return result.deleteCharAt(result.length()-separator.length()).toString();
} 

If you must use ArrayUtils then you could use List.toArray(T[]) (because ArrayUtils is for arrays) and a regular expression to remove { and } on one line like

List<String> test = new ArrayList<>(Arrays.asList("one", "two", "three"));
System.out.println(ArrayUtils.toString(test.toArray(new String[0]))
        .replaceAll("[{|}]", ""));

Output is (as requested)

one,two,three

The String.join(CharSequence, Iterable<? extends CharSequence>) suggested by @Vishnu's answer offers a solution that eschews ArrayUtils (but is arguable better, assuming you can use it) with

String joined2 = String.join(",", test);
System.out.println(joined2);

which outputs the same.

String.join(", ", List.of("one", "two", "three"));

This Java code snippet demonstrates a concise way to concatenate a list of strings into a single string, with a specified delimiter separating each element. It's particularly good for achieving this as a single, compact line of code.

Here's a breakdown:

• List.of("one", "two", "three"): This creates an immutable list containing the strings "one", "two", and "three".

• String.join(", ", ...): This is a static method of the String class introduced in Java 8. It takes two arguments:

  • The delimiter (in this case, ", " - a comma followed by a space) that will be placed between each element.

  • An Iterable (like our List) of elements to be joined.

The method efficiently iterates through the list and builds the resulting string. For the given example, the output will be: "one, two, three".

       List<String> test = new ArrayList<String>();
        test.add("one");
        test.add("two");
        test.add("three");
       Iterator it = test.iterator();

       while(it.hasNext()){

      String s=it.next();
      StringBuilder sb = new StringBuilder();

     sb.append(s);
}