Need Help Urgently please

Question

i'm not a Java expert but i like to think i'm not a beginner.
I've been working on a University Project now for a week and it must be submitted tomorrow . It is a Lexical Analyzer of sorts but for some reason the program freezes and kicks out this error "java.lang.ClassNotFoundException <uncaught>"thread=main", " when i debug to find the problem. it gives no errors on compile and just freezes. i can't figure this out . if anyone can help me it would be greatly appreciated.
Below is the code
My email is : [email protected]
I know the code might be a bit messy or cluttered, so i apologize ahead of time,
package components;
import java.io.Console;
import java.io.InputStreamReader;
import java.util.regex.*;
import java.lang.*;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Scanner;
import java.util.ArrayList;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.Container;
import javax.swing.*;
import javax.swing.filechooser.*;
public class LA extends JPanel implements ActionListener
    static private final String newline = "\n";
    JButton OpenButton, LexButton, ExitButton, ViewLexButton, ViewSymbolButton;
    JTextArea log;
    JFileChooser fc;
    String Filepath="";
    String Filedata="";
    String Scanloc="";
    int strlength=0;
    String temp="";
    String[] reswords={"abstract","do","if","package","synchronized","boolean",
                           "double","implements","private","this","break","else","enum",
                           "import","protected","throw","byte","extends","instanceof",
                           "public","throws","case","false","int","return","transient",
                           "catch","final","interface","short","true","char","finally",
                           "long","static","try","class","float","native","strictfp",
                           "void","const","for","new","super","volatile","continue",
                           "goto","null","switch","while","default","assert"};
    String[] symbols={"+","-","%","/","*","_","(",")","[","]","{","}","||","&&",
                          "=","==","++","--","!=",">",">=","<=","<",".",",",";",":","!","<>","=>","=<","+=","-="};
    String[] symident={"PLUS","MINUS","MODULUS","DIVIDE","MULTIPLY","UNDERSCORE",
                           "OPENING ROUND BRACKET","CLOSING ROUND BRACKET",
                           "OPENING SQUARE BRACKET","CLOSING SQUARE BRACKET","OPENING CURLY BRACE",
                           "CLOSING CURLY BRACE","OR","AND","EQUALS","INSTANCE COMPARE","INCREMENT",
                           "DECREMENT","NOT EQUAL","GREATER THAN","GREATER THAN OR EQUAL TO",
                           "LESS THAN OR EQUAL TO","LESS THAN","DOT","COMMA","SEMI-COLON","COLON","NOT","NOT EQUAL",
                           "EQUAL TO OR GREATER THAN","EQUAL TO OR LESS THAN","PLUS EQUALS","MINUS EQUALS"};
    boolean state=false;
    int i=0;
    int j=0;
    boolean match=false;
    String LexToken="C:\\LexToken.txt";
    String SymTable="C:\\SymbolT.txt";
    String Lexstring="";
    String SymbolTableString=" Symbol |   Kind  | Type \n";
    ArrayList<String> wordarray=new ArrayList<String>();
    String[] temparray1;
    String REPat="";
    public LA()
        super(new BorderLayout());
        log = new JTextArea(20,40);
        log.setMargin(new Insets(5,5,5,5));
        log.setEditable(false);
        JScrollPane logScrollPane = new JScrollPane(log);
        fc = new JFileChooser();
        OpenButton = new JButton("Open a File");
        OpenButton.addActionListener(this);
        ExitButton = new JButton("Exit");
        ExitButton.addActionListener(this);
        LexButton = new JButton("Analyze Lexically");
        LexButton.addActionListener(this);
        ViewLexButton = new JButton("View Token/Lexeme Table");
        ViewLexButton.addActionListener(this);
        ViewSymbolButton = new JButton("View Symbol Table");
        ViewSymbolButton.addActionListener(this);
        JPanel buttonPanel = new JPanel(); //use FlowLayout
        buttonPanel.add(OpenButton);
        buttonPanel.add(LexButton);
        buttonPanel.add(ViewLexButton);
        buttonPanel.add(ViewSymbolButton);
        buttonPanel.add(ExitButton);
        add(buttonPanel, BorderLayout.PAGE_START);
        add(logScrollPane, BorderLayout.CENTER);
    public static String StoreAsString(String FileName)throws Exception
             FileInputStream fis = new FileInputStream(FileName);
          int x= fis.available();
          byte b[]= new byte[x];
          fis.read(b);
          String content = new String(b);
          return content;
     public static void FileWrite(String filename,String Message)throws IOException
          try
          FileWriter fileWriter = new FileWriter(filename);
          BufferedWriter buffWriter = new BufferedWriter(fileWriter);
          buffWriter.write(Message);
          buffWriter.close();
          fileWriter.flush();
          fileWriter.close();
          catch(IOException e)
          System.out.println("Exception "+ e.getMessage());
     public boolean TestForResWord(int val)
          char marker=' ';
          for(i=0;i<reswords.length;i++)
                 if(reswords==wordarray.get(val))
               i=reswords.length+1;
               marker='Y';
     else
               marker='N';
          if(marker=='Y')
               return true;
          else
               return false;
     public boolean patmatch(String patstr)
     Pattern pattern= Pattern.compile(patstr);
          Matcher matcher= pattern.matcher(temparray1[j]);
          boolean temp=false;
          temp=matcher.find();
          if (temp=true)
               return true;
          else
               return false;
public void actionPerformed(ActionEvent e)
try
          if (e.getSource() == OpenButton)
     int returnVal = fc.showOpenDialog(LA.this);
     if (returnVal == JFileChooser.APPROVE_OPTION)
     File file = fc.getSelectedFile();
     Filepath = new String(file.getPath());
     log.append("Opening: " + file.getName() + "." + newline);
     log.append(Filepath + newline);
     Filedata=StoreAsString(Filepath);
     log.append(Filedata);
else
log.append("Open command cancelled by user." + newline);
     else if (e.getSource() == LexButton)
     //int answer = JOptionPane.showConfirmDialog(null,"Are you ready to analyze Lexically?");
          //          if (answer == JOptionPane.YES_OPTION)      // User clicked YES.
                         log.setText("");
               try
                    FileReader rd = new FileReader(Filepath);      // Create the tokenizer to read from a file
                    StreamTokenizer st = new StreamTokenizer(rd);
                    int linenum=0;
                    int colnum=0;
                    st.parseNumbers();           // Prepare the tokenizer for Java-style tokenizing rules
                    st.wordChars('_', '_');
                    st.eolIsSignificant(true);
                    // If whitespace is not to be discarded, make this call
                    st.ordinaryChars(0, ' ');
                    // These calls caused comments to be discarded
                    st.slashSlashComments(true);
                    st.slashStarComments(true);
                    // Parse the file
                    int token = st.nextToken();
                    while (token != StreamTokenizer.TT_EOF)
                    token = st.nextToken();
                         switch (token)
                              case StreamTokenizer.TT_NUMBER:
                              // A number was found; the value is in nval
                              double num = st.nval;
                              linenum=st.lineno();
                              temp=String.valueOf(num);
                              strlength=temp.length();
                              Lexstring=Lexstring+"\nLine : "+linenum+" |Column : "+colnum+" |Token: "+num+" |Lexeme: NUMBER";
                              colnum=colnum+strlength;
                              break;
                              case StreamTokenizer.TT_WORD:
                              // A word was found; the value is in sval
                              //String[] wordarray;
                              boolean match=false;
                              String word = st.sval;
                              int z=0;
                              if(z==0)
                                   wordarray.add(0,word);
                                   z++;
                              linenum=st.lineno();
                              char[] characters=word.toCharArray();
                         for(int x=0;x<characters.length;x++)
                                   for (int y=0;y<symbols.length;y++)
                                        String tempword="";
                                        tempword=tempword+characters[x];
                                        while((z>=1)&&(x<=characters.length))
                                        if (tempword==symbols[y])
                                             if((((characters[x]=='+')||(characters[x]=='-')||(characters[x]=='='))&&((wordarray.get(0+z-1)=="+")||(wordarray.get(0+z-1)=="-")||(wordarray.get(0+z-1)=="=")))||(tempword==wordarray.get(0+z-1))||(((tempword=="=")&&(wordarray.get(0+z-1)=="<"))||((tempword=="=")&&(wordarray.get(0+z-1)==">"))||((tempword==">")&&(wordarray.get(0+z-1)=="="))||((tempword=="<")&&(wordarray.get(0+z-1)=="="))||((tempword==">")&&(wordarray.get(0+z-1)=="<")) ) )
                                                  wordarray.add(0+z,wordarray.get(0+z)+characters[x]);
                                             else
                                             z++;//NOT SURE ABOUT THIS INCREMENT
                                             wordarray.add(0+z,""+characters[x]);
                                             z++;
                                   wordarray.add(0+z,wordarray.get(0+z)+characters[x]);
                         while(state=false)
                              overhere:                                                                       
                                                  for(j=0;j<wordarray.size();j++)
                                   String[] temparray1=(String[])wordarray.toArray();
                              temp=temparray1[j];
                                   strlength=temp.length();
                              if(strlength>1)
                              REPat="[\\W]";
                              match=patmatch(REPat);     
                              if(match=false)
                              for(i=0;i<reswords.length;i++)
                                   if(reswords[i]==wordarray.get(j))
                                        String lexemestr=reswords[i].toUpperCase();
                                        Lexstring=Lexstring+"\nLine : "+linenum+" |Column : "+colnum+" |Token: "+wordarray.get(j)+" |Lexeme: OP_"+lexemestr;
                                        colnum=colnum+strlength;
                                        i=reswords.length+1;
                                        j++;
                                        break overhere;
                              REPat="[(?i)[a-z][\\w*]*]";
                              match=patmatch(REPat);
                              if(match=true)
                                   boolean test1=false;
                                        test1=TestForResWord(j-1);
                                   boolean test2=false;
                                        test2=TestForResWord(j-2);
                                   boolean test3=false;
                                        test3=TestForResWord(j-3);
                                   String[] temparray2=(String[])wordarray.toArray();
                              temp=temparray2[j];
                                   strlength=temp.length();
                                   Lexstring=Lexstring+"\nLine : "+linenum+" |Column : "+colnum+" |Token: "+temp+" |Lexeme: VARIABLE";
                                   if(((test1==true)&&(test2==true)&&(test3==true))||((test1==true)&&(test2==true)&&(test3==false)))
                                        SymbolTableString=SymbolTableString+" "+temp+" | Method | "+wordarray.get(j-1)+"\n";
                                   else if((test1==true)&&(test2==false)&&(test3==false))
                                        SymbolTableString=SymbolTableString+" "+temp+" | Variable | "+wordarray.get(j-1)+"\n";
                                   colnum=colnum+strlength;
                                   i=reswords.length+1;
                              else if(match=false)
                              String[] temparray3=(String[])wordarray.toArray();
                              temp=temparray3[j];
                              strlength=temp.length();
                              Lexstring=Lexstring+"\nLine : "+linenum+" |Column : "+colnum+" |Token: "+temp+" |Lexeme: INVALID_WORD";
                              colnum=colnum+strlength;
                              i=reswords.length+1;
                              else
                              for(i=0;i<symbols.length;i++)
                                        if(symbols[i]==wordarray.get(j))
                                        Lexstring=Lexstring+"\nLine : "+linenum+" |Column : "+colnum+" |Token: "+wordarray.get(j)+" |Lexeme: OP_"+symident[i];
                                        colnum=colnum+strlength;                                    
                                        i=symbols.length+1;
                              else if(strlength==1)
                                   for(i=0;i<symbols.length;i++)
                                        if(symbols[i]==wordarray.get(j))
                                        Lexstring=Lexstring+"\nLine : "+linenum+" |Column : "+colnum+" |Token: "+wordarray.get(j)+" |Lexeme: OP_"+symident[i];
                                        colnum=colnum+strlength;                                    
                                        i=symbols.length+1;
                                        else
                                        boolean test1=false;
                                        test1=TestForResWord(j-1);
                                   boolean test2=false;
                                        test2=TestForResWord(j-2);
                                   boolean test3=false;
                                        test3=TestForResWord(j-3);
                                        Lexstring=Lexstring+"\nLine : "+linenum+" |Column : "+colnum+" |Token: "+wordarray.get(j)+" |Lexeme: VARIABLE";
                                        if(((test1==true)&&(test2==true)&&(test3==true))||((test1==true)&&(test2==true)&&(test3==false)))
                                                  SymbolTableString=SymbolTableString+" "+temp+" | Method | "+wordarray.get(j-1)+"\n";
                                        else if((test1==true)&&(test2==false)&&(test3==false))
                                                  SymbolTableString=SymbolTableString+" "+temp+" | Variable | "+wordarray.get(j-1)+"\n";
                                        colnum=colnum+strlength;
                                        i=symbols.length+1;     
                                                  if(wordarray.size()>=j)
                                   state=true;
                              //colnum=colnum+strlength;
                              break;
                              case '"':
                              // A double-quoted string was found; sval contains the contents
                              String dquoteVal = st.sval;
                              linenum=st.lineno();
                              strlength=dquoteVal.length();
                              colnum=colnum+strlength;
                              break;
                              case '\'':
                              // A single-quoted string was found; sval contains the contents
                              String squoteVal = st.sval;
                              linenum=st.lineno();
                              strlength=squoteVal.length();
                              colnum=colnum+strlength;
                              break;
                              case StreamTokenizer.TT_EOL:
                              // End of line character found
                              colnum=0;
                              break;
                              case StreamTokenizer.TT_EOF:
                              // End of file has been reached
                              break;
                              default:
                              // A regular character was found; the value is the token itself
                              char ch = (char)st.ttype;
                              break;
                              rd.close();
                    catch (IOException ex)
                         System.err.println("Exception with file! "+ex.getMessage());
                         log.append("Lexical Analysis Complete");
               //     else if (answer == JOptionPane.NO_OPTION)      // User clicked NO.
     //          log.append("Analyze command decided against by user." + newline);
          //          else if (answer == JOptionPane.CANCEL_OPTION)      // User clicked CANCEL.
     //          log.append("Analyze command cancelled by user." + newline);
     FileWrite(LexToken,Lexstring);
     FileWrite(SymTable,SymbolTableString);
     else if (e.getSource() == ViewLexButton)
          log.setText("");
          Filedata=StoreAsString("C:\\LexToken.txt");
          log.append(Filedata);
          log.append("LexToken.txt has been stored at C:\\LexToken.txt");
else if (e.getSource() == ViewSymbolButton)
          log.setText("");
          Filedata=StoreAsString("C:\\SymbolT.txt");
          log.append(Filedata);
          log.append("SymbolT.txt has been stored at C:\\SymbolT.txt");
else if (e.getSource() == ExitButton)
System.exit (0);
catch(FileNotFoundException ex)
               System.err.println("File not found! "+ex);
     catch(IOException ex)
               System.err.println("Exception with file! "+ex);
     catch(Exception ex)
               System.err.println("Exception with file! "+ex);
/** Returns an ImageIcon, or null if the path was invalid. */
protected static ImageIcon createImageIcon(String path)
java.net.URL imgURL = LA.class.getResource(path);
if (imgURL != null) {
return new ImageIcon(imgURL);
} else {
System.err.println("Couldn't find file: " + path);
return null;
private static void createAndShowGUI()
//Create and set up the window.
JFrame frame = new JFrame("LA");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
JComponent newContentPane = new LA();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
//Display the window.
frame.pack();
frame.setVisible(true);
public static void main(String[] args)throws IOException
// javax.swing.SwingUtilities.invokeLater(new Runnable()
// public void run()
createAndShowGUI();

Answer 1

I started to look at that code and saw that massive if statement and decided this was far too messy for me to waste my time on. That being said, I still have some recommendations.
First, I have a question: How are you debugging this? What are you doing to try to identify where your hang-up is occurring? Have you tried anything yourself yet, or is this your first attempt?
Second, my recommendation would be to add a few System.out.println() statements in that mess of for/while loops that you have to see how far into them you're getting and when/if you're ever exiting them. Once you don't get to one of those print statements, then you will know where you're buggered.
So why don't you take a little time and try to narrow your code down to a block or two to see where you're problems are coming from. Then you can come back and give us a place to look, because - quite frankly - no one here is going to want to sift through that mess of code.
Good luck.