Need help with Java please

I don't know java, but that is for an assignment at school, I was given the code and I am supposed to just pipe the output to a file and submit it.

I am trying to compile the following code using javac.
I am able to compile

javac Server.java

but when I do java Server.java I get

Exception in thread "main" java.lang.NoClassDefFoundError: Server/java

I see they are saying that server is not included in main, but that is the exact code I was given so I would presume that there won't be a stupid mistake like that.
here is the code
-----------------------------------------------------------
Exception in thread "main" java.lang.NoClassDefFoundError: Server/java

import java.net.*;
import java.io.*;

public class Server
{
public static void main(String[] args) throws IOException{
Socket client= null;
PrintWriter pout=null;
ServerSocket sock=null;

try{
sock= new ServerSocket(5155);
// now listen for connections

while(true){
client= sock.accept();

// we have a connection
pout = new PrintWriter(client.getOutputStream(), true);

// write the date to the socket
pout.println(new java.util.Date().toString());

pout.close();
client.close();
}
}
catch (IOException ioe) {
System.err.println(ioe);
}
finally {
if (client !=null)
client.close();
if (sock !=null)
sock.close();
}
}
}

If anyone has any suggestions I would appreciate it. Thanks

Try just java Server

Remember, you're running your Class file, not your java file...

Okay I'll give it a try, and I'll post what happened