import  java .util.*;
public class SystemTest
{
public static void main(String[] args)
{
//????arraycopy????????????????????????
int[] src = {1??2??3??4??5??6??7??8??9};
System.out.println("System.arraycopy");
int[] dst = new int[src.length];
System.arraycopy(src?? 0?? dst?? 0?? src.length);
System.out.println("src = "+Arrays.toString(src));
System.out.println("dst = "+Arrays.toString(dst));
//??????????Arrays.copyOf??????????????????
System.out.println("Arrays.copyOf");
int[] dst1 = Arrays.copyOf(src?? src.length);
System.out.println("src = "+Arrays.toString(src));
System.out.println("dst1 = "+Arrays.toString(dst1));
//????currentTimeMillis()
System.out.println("currentTimeMillis "+System.currentTimeMillis());
//????nanoTime()??????????????????????壬????????????????????
System.out.println("nanoTime "+System.nanoTime());
long dt=System.nanoTime();
dt = dt - System.nanoTime();
System.out.println("dt = "+dt);
//????getenv()????????Map???÷???????????
System.out.println("System.getenv");
Map<String??String> env = System.getenv();
Iterator it = env.entrySet().iterator();
while(it.hasNext())
{
Map.Entry a = (Map.Entry)it.next();
System.out.println("<"+a.getKey()+"> = <"+a.getValue()+">;");
}
//getProperties()????????Map???÷???????????
System.out.println("System.getProperties");
Properties p = System.getProperties();
p.list(System.out);
System.out.println("Hello World!");
}
}