How to concat string values in array list

Question

I need to print all arraylist values at a time using concat.

Here is my code:

ArrayList lst = new ArrayList();
lst.add(\"hi\"         


        

Answer 1

Please prefer the List interface to the ArrayList concrete type. Assuming you are using Java 8+, you might use a Stream and Collectors.joining (and Arrays.asList) like

List lst = Arrays.asList("hi", "hello");
String r = lst.stream().collect(Collectors.joining(" "));
System.out.println(r);

Which outputs

hi hello

As requested.