wtf is with this code

gistfile1.java

package net.rymate.markoveriewer;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.jibble.jmegahal.JMegaHal;
import org.jibble.pircbot.PircBot;

/**
 *
 * @author Ryan
 */
public class AIBot extends PircBot {

    public AIBot() {
        this.setName("markoveriewer");
    }

    public void onMessage(String channel, String sender, String login, String hostname, String message) {
        File globalFile = new File("brain");
        if (message.startsWith("markoverviewer, emulate ") || message.startsWith("markoverviewer: emulate ")) {
            try {
                String username = message.substring(message.lastIndexOf(" ") + 1);
                System.out.println("User is \"" + username + "\"");
                File userFile = new File(username.toLowerCase());
                JMegaHal hal = new JMegaHal();
                hal.addDocument(userFile.toURI().toString());
                sendMessage(channel, "<" + username + "> " + hal.getSentence());
            } catch (IOException ex) {
                Logger.getLogger(AIBot.class.getName()).log(Level.SEVERE, null, ex);
            }

        } else if (message.startsWith("markoverviewer, what is ") || message.startsWith("markoverviewer: what is ")) {
            try {
                System.out.println("Object is \"" + message.substring(message.lastIndexOf(" ") + 1) + "\"");

                JMegaHal hal = new JMegaHal();
                hal.addDocument(globalFile.toURI().toString());
                sendMessage(channel, hal.getSentence(message.substring(message.lastIndexOf(" ") + 1)));
            } catch (IOException ex) {
                Logger.getLogger(AIBot.class.getName()).log(Level.SEVERE, null, ex);
            }
        } else {
            sender = sender.replace("_", "");
            File userFile = new File(sender.toLowerCase());
            try {
                if (!userFile.exists() && !globalFile.exists()) {
                    userFile.createNewFile();
                    globalFile.createNewFile();
                }
                appendToFile(userFile, message);
                appendToFile(globalFile, message);
            } catch (IOException ex) {
                Logger.getLogger(AIBot.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

    }

    public void appendToFile(File f, String s) throws IOException {
        FileWriter fileWritter = new FileWriter(f.getName(), true);
        BufferedWriter bufferWritter = new BufferedWriter(fileWritter);
        bufferWritter.write(s + ".");
        bufferWritter.write("\n");
        bufferWritter.close();
    }
}