🚀 go-pugleaf

I have a simple test.The code is belowing,
--------------------------------------------------
import java.applet.*;
import java.awt.*;
import java.net.*;
import java.io.*;
public class Test extends Frame{
	static Vector clients = new Vector(10);
        ... ...
}
---------------------------------------------------
When I compile the Test.java.
Show error "Class Vector not found"
I use jdk1.2.1. The classpath is 'C:\Windows\java\Class\classes.zip'.
Isn't Vector class included in java.lang package?
How that error happens?

Thanks.