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」の「0」番目から「array.length」分を「new_array」の「0」番目以降にコピーする
        System.arraycopy(array, 0, new_array, 0, array.length);
 
        new_array[array.length] = "3";
 
        //実行結果
        //1
        //2
        //3
        for(String str : new_array){
            System.out.println(str);
        }
    }
}