Collections.copy problems. . .

dunke0921

import java.util. *;

public class Copy
{
public static void main (String [] args)
{
List source = Arrays.asList ("three Two Yo Yo six five Four" .split (""));
List dest = Arrays.asList ("in the matrix" .split ("m"));
Collections.copy (dest, source);
System.out.println (dest);
}
}
Don't know why an exception is thrown here?

chen96542

Collections jdk source code

public static <T> void copy (List <? super T> dest, List <? extends T> src) {
        int srcSize = src.size (); // source array
        if (srcSize> dest.size ())
            throw new IndexOutOfBoundsException ("Source does not fit in dest");
        // If the size () of the source array> size () of the destination array, then IndexOutOfBoundsException is thrown

seakey

Collections.copy (dest, source);
Insufficient space or type mismatch will throw an exception

dunke0921

knock off

lan25447846

The length of the target array is 0 before initialization, you want to display the set target array length> source array length, and then copy.