public class ArrayCopy{
    public static void main(String args[]){
        String[] array = new String[3];
        array[0] = "0";
        array[1] = "1";
        array[2] = "2";

        String[] new_array = new String[array.length+1];
        
        //「array(引数1)」の「0(引数2)」番目から「array.length(引数5)」分を「new_array(引数3)」の「0(引数4)」番目以降にコピーする
        System.arraycopy(array, 0, new_array, 0, array.length);
        
        //new_arrayの最後尾に「3」を追加
        new_array[array.length] = "3";

        //実行結果
        //0
        //1
        //2
        //3
        for(String str : new_array){
            System.out.println(str);
        }
    }
}