Java - List <>

tengo este codigo para un servidor yo solo hice el cliente este servidor me fue proporcionado por un maestro pero me marca errores( tengo la clase connection):
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
C:\Documents and Settings\Alumno\Escritorio\mod15_network\exercise1\server\ChatServer.java:29: <identifier> expected
private List<Connection> connections = null;
^
C:\Documents and Settings\Alumno\Escritorio\mod15_network\exercise1\server\ChatServer.java:31: <identifier> expected
private Map<String,String> hostToStudentMap = null;
^
C:\Documents and Settings\Alumno\Escritorio\mod15_network\exercise1\server\ChatServer.java:46: ';' expected
for ( Connection c : connections ) {
^
C:\Documents and Settings\Alumno\Escritorio\mod15_network\exercise1\server\ChatServer.java:49: illegal start of expression
}
^
C:\Documents and Settings\Alumno\Escritorio\mod15_network\exercise1\server\ChatServer.java:87: '(' or '[' expected
this.connections = new ArrayList<Connection>(maxConnections);
^
C:\Documents and Settings\Alumno\Escritorio\mod15_network\exercise1\server\ChatServer.java:88: '(' or '[' expected
this.hostToStudentMap = new HashMap<String,String>(15);
^
6 errors
Exit code: 1
There were errors
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

import java.io.*;
import java.net.*;
import java.util.*;
import java.applet.*;
import javax.swing.*;

public class ChatServer {

public static void main(String[] args) {
ChatServer cs = new ChatServer();
cs.go();
}

public final static int DEFAULT_PORT = 2000;
public final static int DEFAULT_MAX_BACKLOG = 5;
public final static int DEFAULT_MAX_CONNECTIONS = 20;
public final static String DEFAULT_HOST_FILE = "hosts.txt";
public final static String DEFAULT_SOUND_FILE = "file:gong.au";
public final static String MAGIC = "Yippy Skippy";

private String magic = MAGIC;

private int port = DEFAULT_PORT;
private int backlog = DEFAULT_MAX_BACKLOG;
private int numConnections = 0;
private int maxConnections = DEFAULT_MAX_CONNECTIONS;
private String hostfile = DEFAULT_HOST_FILE;
private String soundfile = DEFAULT_SOUND_FILE;
private List<Connection> connections = null;
private AudioClip connectSound = null;
private Map<String,String> hostToStudentMap = null;

//
// Methods for the Connection class
//

String getMagicPassphrase() {
return magic;
}

String getStudentName(String host) {
return hostToStudentMap.get(host);
}

void sendToAllClients(String message) {
for ( Connection c : connections ) {
c.sendMessage(message);
}
}

void playMagicSound() {
if ( connectSound != null ) {
connectSound.play();
}
}

synchronized void closeConnection(Connection connection) {
connections.remove(connection);
numConnections--;
notify();
}

//
// Private methods
//

private void go() {
String portString = System.getProperty("port");
if (portString != null) port = Integer.parseInt(portString);
this.port = port;

String backlogString = System.getProperty("backlog");
if (backlogString != null) backlog = Integer.parseInt(backlogString);

String hostFileString = System.getProperty("hostfile");
if (hostFileString != null) hostfile = hostFileString;

String soundFileString = System.getProperty("soundfile");
if (soundFileString != null) soundfile = soundFileString;

String magicString = System.getProperty("magic");
if (magicString != null) magic = magicString;

String connections = System.getProperty("connections");
if (connections != null) maxConnections = Integer.parseInt(connections);

this.connections = new ArrayList<Connection>(maxConnections);
this.hostToStudentMap = new HashMap<String,String>(15);

System.out.println("Server settings:\n\tPort="+port+"\n\tMax Backlog="+
backlog+"\n\tMax Connections="+maxConnections+
"\n\tHost File="+hostfile+"\n\tSound File="+soundfile);

createHostList();

try {
URL sound = new URL(soundfile);
connectSound = Applet.newAudioClip(sound);
} catch(Exception e) {
e.printStackTrace();
}

// Begin the processing cycle
processRequests();
}

private void createHostList() {
File hostFile = new File(hostfile);
try {
System.out.println("Attempting to read hostfile hosts.txt: ");
FileInputStream fis = new FileInputStream(hostFile);
InputStreamReader isr = new InputStreamReader(fis);
BufferedReader br = new BufferedReader(isr);
String aLine = null;
while((aLine = br.readLine()) != null) {
int spaceIndex = aLine.indexOf(' ');
if (spaceIndex == -1) {
System.out.println("Invalid line in host file: "+aLine);
continue;
}
String host = aLine.substring(0,spaceIndex);
String student = aLine.substring(spaceIndex+1);
System.out.println("Read: "+student+"@"+host);
hostToStudentMap.put(host,student);
}
} catch(Exception e) {
e.printStackTrace();
}
}

private void processRequests() {
ServerSocket serverSocket = null;
Socket communicationSocket;

try {
System.out.println("Attempting to start server...");
serverSocket = new ServerSocket(port,backlog);
} catch (IOException e) {
System.out.println("Error starting server: Could not open port "+port);
e.printStackTrace();
System.exit(-1);
}
System.out.println ("Started server on port "+port);

// Run the listen/accept loop forever
while (true) {
try {
// Wait here and listen for a connection
communicationSocket = serverSocket.accept();
handleConnection(communicationSocket);
} catch (Exception e) {
System.out.println("Unable to spawn child socket.");
e.printStackTrace();
}
}
}

private synchronized void handleConnection(Socket connection) {
while (numConnections == maxConnections) {
try {
wait();
} catch(Exception e) {
e.printStackTrace();
}
}
numConnections++;
Connection con = new Connection(this, connection);
Thread t = new Thread(con);
t.start();
connections.add(con);
}
}