Blocking Logger implementation that should have gotten me expelled from University

LogFile.java

/**
 * @(#)LogFile.java
 *
 * Copyright (c) 2001 Andrew Lee Rubinger
 *
 * @author Andrew Lee Rubinger
 * @version 1.0
 */
 
package com.alrubinger.util;

import java.io.File;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.IOException;

import java.sql.Timestamp;

/**
 * This class defines a custom logging system
 * which may be used within the scope of an
 * entire application, and is not limited to 
 * Servlet classes.
 */
 
public class LogFile
{
    /**
     * The PrintWriter Object used 
     */
    protected PrintWriter writer;
    
    /**
     * The directory in which to place the 
     * log file 
     */
    protected String directory = "logs";
    
    /**
     * The prefix of the filename
     */
    protected String prefix = "debug";
    
    /**
     * The suffix of the filename
     */
    protected String suffix = "log";
    
    /**
     * The DateStamp used to indicate 
     * the date of the file
     */
    protected String dateStamp;
    
    /**
     * Default constructor
     */
    public LogFile()
    {
        setDateStamp();
        openStream(directory,prefix,suffix);
    }
    
    /**
     * Constructor setting specified
     * directory, prefix, and suffix
     * attributes of the filename.
     */
    public LogFile(String newDirectory,String newPrefix,String newSuffix)
    {
        // Override default values to new ones
        directory = newDirectory;
        prefix = newPrefix;
        suffix = newSuffix;
        
        setDateStamp();
        setDirectory(newDirectory);
        setPrefix(newPrefix);
        setSuffix(newSuffix);
        openStream(directory,prefix,suffix);
    }
    
    
    // Mutator Methods ---------------------|||
    
    /**
     * Sets the prefix to the specifed value
     *
     * @param newPrefix - The new prefix value
     */
    protected void setPrefix(String newPrefix)
    {
        prefix = newPrefix;
    }
    
    /**
     * Sets the suffix to the specified value
     *
     * @param newSuffix - The new suffix value
     */
    protected void setSuffix(String newSuffix)
    {
        suffix = newSuffix;   
    }
    
    /**
     * Sets the directory to the specified value
     *
     * @param newDirectory - The new directory value
     */
    protected void setDirectory(String newDirectory)
    {
        directory = newDirectory;
    }
    
    protected String setDateStamp()
    {
        dateStamp = formatCurrentDate();
        return dateStamp;
    }
    
    // Accessor Methods --------------------|||
    
    /**
    * Returns the prefix
    *
    * @return prefix - The prefix used for log 
    *                   file names
    */
    protected String getPrefix()
    {
        return prefix;   
    }
    
    /**
    * Returns the suffix
    *
    * @return suffix - The suffix used 
    *                   for log file names
    */
    protected String getSuffix()
    {
        return suffix;   
    }
    
    /**
    * Returns the current date and time in 
    * format YYYY:MM:DD HH:MM:SS
    *
    * @return currentDateTime - The current
    *           date and time in format
    *           YYYY:MM:DD HH:MM:SS
    */
    protected String formatCurrentDateTime()
    {
        Timestamp currentTime = new Timestamp(System.currentTimeMillis());
        String currentDateTime = currentTime.toString().substring(0,19);
        return currentDateTime;
    }
    
    /**
    * Returns the current date in
    * format YYYY-MM-DD
    *
    * @return currentDateString - The Current Date 
    *                          in YYYY-MM-DD
    */
    protected String formatCurrentDate()
    {
        return formatCurrentDateTime().substring(0,10);
    }
    
    /**
     * Returns the current date in
     * format HH:MM:SS
     *
     * @return currentDateString - The Current Time 
     *                          in HH:MM:SS
     */
    protected String formatCurrentTime()
    {
        return formatCurrentDateTime().substring(11,19);
    }
    
    /**
     * Returns the date which is currently
     * being used by the LogFile.  Can be 
     * compared to the current date
     * to ensure they match up
     */
    protected String getCurrentDateStamp()
    {
        return dateStamp;   
    }
    
    /**
     * Prints the specified String
     * to the log file along with 
     * timestamp
     *
     * @param logEntry - The String to log
     */
    public synchronized void log(String logEntry)
    {
        // The date has changed; go to new file
        if(formatCurrentDate()!=getCurrentDateStamp())
        {
            closeStream();
            setDateStamp();
            openStream(directory,prefix,suffix);
        }
        
        // Log the message along with timestamp
        writer.print(formatCurrentTime());
        writer.print(" - ");
        writer.println(logEntry);
    }
    
    /**
     * Prints the full stack trace of 
     * an exception to the log
     *
     * @param e The Exception whose stack trace
     *               should be printed
     */
    public synchronized void logStackTrace(Exception e)
    {
        e.printStackTrace(writer);
    }
    
    /**
     * Attempts to close the PrintWriter 
     * output stream. 
     */
    private void closeStream()
    {
        if(writer==null) return;
        
        writer.flush();
        writer.close();
        writer = null;
    }
    
    /**
     * Attempts to open the PrintWriter
     * stream to the filename set by the prefix, 
     * suffix, and current date
     */
    private void openStream(String thisDirectory,String thisPrefix,String thisSuffix)
    {
        File newDirectory = new File(thisDirectory);
        if(!newDirectory.isAbsolute())
        {
            newDirectory = new File(System.getProperty("catalina.home") +
                                        File.separator + directory);   
        }
        
        newDirectory.mkdirs();
        
        try
        {
            String filePath = newDirectory.getAbsolutePath() + File.separator +
                                prefix + "_log_" + dateStamp + "." + suffix;
            // Set the PrintWriter to append to the end of the file and auto-flush
            writer = new PrintWriter(new FileWriter(filePath,true),true);
        }
        catch(IOException ioe)
        {
            writer = null;   
        }
    }
}