How to pass varargs by reference in Java

Question

I\'m writing a method that receives any number of arguments and returns them modified. I have tried with varargs but it doesn\'t work, here you can see a simplified version of t

Answer 1

Java is pass by value. You cannot achieve what you wish. Instead you can return the modified array from addPrefix() function.

public static void main(String args[]) {

    String hello = "hello";
    String world = "world";

    String[] elements = addPrefix(hello, world);

    for (int i = 0; i < elements.length; i++) {
        System.out.println(elements[i]);
    }




}

public static String[] addPrefix(String... elements) {
    for (int i = 0; i < elements.length; i++) {
        elements[i] = "prefix_" + elements[i];
    }

    for (int i = 0; i < elements.length; i++) {
        System.out.println(elements[i]);
    }

    return elements;
}

and output

prefix_hello
prefix_world
prefix_hello
prefix_world