出现不同数组元素顺序颠倒

package xiancheng;
import java.util.Arrays;
public class Test {
	public static void swap(int a []) {
		int len=a.length ;
		for (int i = 0; i < len/2; i++) {
			int b=a[i];
			a[i]=a[len-1-i];
			a[len-1-i]=b;
		}
	}

	 public static void main(String[] args) {
			int [] a=new int [] {
					(int)(Math.random()*1000),
					(int)(Math.random()*1000),
					(int)(Math.random()*1000),
					(int)(Math.random()*1000),
					(int)(Math.random()*1000),
					
			};
		System.out.println(a);
		System.out.println("出现数组排序如下");
		System.out.println(Arrays.toString(a));
		swap(a);
		System.out.println(a);//数组地址没有变化
		System.out.println("数组后排序如下");
		System.out.println(Arrays.toString(a));
		
	}

	
}