Java Programming

Help! My final project for a class involves writing a program that both compresses a file (dictionary must use a hash map) and decompresses a file (using an array list). The program uses the BitInputStream and BitOutputStream classes. I have spent weeks trying to get this to work and I cannot (and the project is already overdue by a day!) Can anyone help? Here is what I have...

/** A instance of this class has methods that perform LZW compression and
**  decompression.  It assumes that the source alphabet is comprised of the
**  128 ASCII chars.  (Hence, it can compress/decompress only text files.)
**
**  @author Kevin Behr and R. McCloskey
**  @version December 2006
**
**  Logic for Compression/Decompression algorithms obtained from 
**  http://marknelson.us/1989/10/01/lzw-data-compression/
*/

   import java.io.*;
   import java.util.HashMap;    // to represent dictionary in compress()
   import java.util.ArrayList;  // to represent dictionary in decompress()

    public class LZWForText3 {    
   
   /**  <insert comments describing what this method does>
   */
       public void compress(InputStream input, OutputStream output)
       throws IOException
      {
          
      // for doing bit-oriented writing
         BitOutputStream bos = new BitOutputStream(output);
      
      /* initialize the dictionary to contain an entry for each
      ** length one string corresponding to an ASCII character
      */
      
         HashMap<String, Integer> hMap = new HashMap<String, Integer>();
      
         for(int i=0; i <= 127; i++)
         {
            String z = Character.toString((char)i);
            hMap.put(z,i);
         }
      
      /* read the input data from 'input' and
      ** write its compressed form to 'bos'
      */
      
         int read = input.read();
         String str = Character.toString((char)read);
      	
         int code;
         int SIZE = 128;
      	
         read = input.read();
      
         while(read != -1)
         {
            if(hMap.containsKey(str + read))
            {
               str = str + read;
            }
            else
            {
               code = ((Integer)hMap.get(str)).intValue(); 
               bos.writeBit(code); 
               hMap.put(str + read, SIZE); 
               str = Character.toString((char)read);
            
            }   
         	
            code = ((Integer)hMap.get(str)).intValue();
            bos.writeBit(code);
         
            bos.flush();
         }
      }
   
   
   /**  <insert comments describing what this method does>
   */
       public void decompress(InputStream input, OutputStream output)
       throws IOException
      {
      
      // for doing bit-oriented reading (as opposed to byte-oriented)
         BitInputStream bis = new BitInputStream(input);
      
      // for doing character-oriented writing (as opposed to byte-oriented)
         PrintWriter pw = new PrintWriter(output);
      
      /* initialize the dictionary to contain an entry for each
      ** length one string corresponding to an ASCII character
      */
      
         ArrayList<String> aList = new ArrayList<String>();
      
         for(int i=0; i <= 127; i++)
         {
            String z = Character.toString((char)i);
            aList.add(z);
         }
      
      /* read the input data from 'bis' and
      ** write its decompressed form to 'pw'
      */
      
         int SIZE = 128;
      
         int read = bis.readBit();
         String str = Character.toString((char)read);
         String str2 = "";
      	
         while((read = bis.readBit()) != -1)
         {
            pw.print(str);
            read = bis.readBit();
         
            if(read == SIZE)
            {
               str2 = str + str.charAt(0);
            }
            else
            {
               str2 = aList.get(read);
            }
                 
            aList.add(SIZE, str + str2.charAt(0));
            SIZE++;
            str = str2;
         }
      
         pw.print(aList.get(0));
         pw.flush();
      
      }
   }