一个简单的程序package了，编译却不生成jar
GetString类：package get;
public class GetString
{
public GetString(int i,int j)
{
String string1="I don't wanna say goodbye to you";
int len=string1.length();
char []a=new char[len];
a[0]=string1.charAt(i);
String string3=string1.substring(i,j);
System.out.println("the char at "+i+" is:"+a[0]);//获取字符
System.out.println("the string from"+i+"to"+j+"is:");//获取子串
System.out.println(string3);
}
}
调用它的TestGetString：
import get.GetString;
public class TestGetString
{
public static void main(String[] args)
{
GetString loca=new GetString(8,17);
}
}
问题：如上程序要怎样改才能编译生成*.jar的文件？
