I tried to add UUID banning from here... [Only registered and activated users can see links. ]

One of the error codes:
Code:
static String uidForUser = null;
	public static void getUidForUser(Client c, String name) {
		  File file = new File("./Data/characters/" + name + ".txt");
	        StringBuffer contents = new StringBuffer();
	        BufferedReader reader = null;
	        boolean error = false;
	        try {
	            reader = new BufferedReader(new FileReader(file));
	            String text = null;
	            int line = 0;
	            int done = 0;
	            // repeat until all lines is read
	            while ((text = reader.readLine()) != null && done == 0) {
	            	text = text.trim();
	            	line += 1;
	            	if(line >= 6) {
	            		text = text.trim();
	            		int spot = text.indexOf("=");
	            		String token = text.substring(0, spot);
	            		token = token.trim();
	            		String token2 = text.substring(spot + 1);
	            		token2 = token2.trim();
	            			if(token.equalsIgnoreCase("UUID")) {
	            				uidForUser = token2;
	            				done = 1;
	            			}
	        			}
	            }
	        } catch (FileNotFoundException e) {
	            e.printStackTrace();
	            error = true;
	            c.sendMessage("Could not find the character file "+name+".txt");
	        } catch (IOException e) {
	            e.printStackTrace();
	            error = true;
	            c.sendMessage("A problem occured while trying to read the character file for "+name+".");
	        } finally {
	            try {
	                if (reader != null) {
	                    reader.close();
	                }
	            } catch (IOException e) {
	                e.printStackTrace();
	            }
	        }
	        //System.out.println(macForUser);
	        if(!error) {
	        bannedUid.remove(uidForUser);
			deleteFromFile("./Data/bans/UUIDBans.txt", uidForUser);
			c.sendMessage("@[email protected] banned user "+name+" with the UUID address of "+uidForUser+".");
	        }
	}
Error:
Code:
src\server\model\players\Client.java:472: error: cannot find symbol
                UUID = RS2LoginProtocolDecoder.UUID;
                       ^
  symbol:   variable RS2LoginProtocolDecoder
  location: class Client
src\server\Connection.java:142: error: cannot find symbol
                  File file = new File("./Data/characters/" + name + ".txt");
                  ^
  symbol:   class File
  location: class Connection
src\server\Connection.java:142: error: cannot find symbol
                  File file = new File("./Data/characters/" + name + ".txt");
                                  ^
  symbol:   class File
  location: class Connection
src\server\Connection.java:168: error: cannot find symbol
                } catch (FileNotFoundException e) {
                         ^
  symbol:   class FileNotFoundException
  location: class Connection
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
4 errors
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