java實現正確的數組拷貝

import java.lang.reflect.Array;
import java.util.Arrays;

public class Test{
    public static void main(String[] args){
        int[] a = {1,2,3};
        a = (int[])goodCopyOf(a,10);
        System.out.println(Arrays.toString(a));
        String[] b = {"Tom","Dick","Harry"};
        b = (String[]) goodCopyOf(b,10);
        System.out.println(Arrays.toString(b));
    }




    public static Object goodCopyOf(Object a,int newLength){
        Class cl = a.getClass();
        if(!cl.isArray())
            return null;
        Class componentType = cl.getComponentType();
        int length = Array.getLength(a);
        Object newArray = Array.newInstance(componentType,newLength);
        System.arraycopy(a,0,newArray,0,Math.min(length,newLength));
        return newArray;
    }

}