Help on 2 error messages / code request please

Question

Why am I getting this error message about an abstract when I'm not declearing one.
error messages I'm getting below -----------
.\LkList.java:26: Method LinkedList getList() requires a method body. Otherwise declare it as abstract.
public LinkedList getList();
DCalc.java:10: class LkList is an abstract class. It can't be instantiated.
LkList Expression =new LkList(exp);
code below ------------------------------
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;
import java.util.*;
class JCal extends JFrame implements KeyListener
     JLabel answer, expression;
     JButton b1, b2, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16, b17, b18, b19,
          b20, b21, b22, b23, b24, b25, b26, b27;
     JMenuBar menuBar;
     JMenu menu;
     JMenuItem menuItem, menuItem1;
     LkList equation;
     String exp="";
     String ans="";
     double memory=0;
     public JCal()
     {     super("Nicks Swing Calculator");
//------------------------- labels ---------------------------------------------
          answer = new JLabel(" 0 "); //Answer Lable
          answer.setBounds (20, 20, 220, 30);
          answer.setBorder (BorderFactory.createLoweredBevelBorder());
          answer.setBackground (Color.pink);
answer.setHorizontalAlignment (SwingConstants.RIGHT);
          expression = new JLabel(" 0 "); // Expression Lable
          expression.setBounds (20, 55, 220, 30);
          expression.setBorder (BorderFactory.createLoweredBevelBorder());
          expression.setBackground (Color.white);
//------------------------- menu -------------------------------------------------
          menuBar = new JMenuBar();
          setJMenuBar (menuBar);
          menu = new JMenu ("File");
          menuItem = new JMenuItem (" Help", new ImageIcon("help.gif"));
          menuItem1 = new JMenuItem (" Splash Page");
          menuItem.addActionListener(new ActionListener() // Help menu
          {     public void actionPerformed(ActionEvent e)
               {     new JHelp();
menuItem1.addActionListener(new ActionListener() // Splash Page
          {     public void actionPerformed(ActionEvent e)
               {     new JSplash();
//------------------------ buttons ------------------------------------------------
          JButton b1 = new JButton (new ImageIcon ("mc.gif")); // MR button
          b1.setBounds(20, 100, 55, 50);
          JButton b2 = new JButton (new ImageIcon ("mr.gif")); // MC button
          b2.setBounds(75, 100, 55, 50);
JButton b3 = new JButton (new ImageIcon ("ms.gif")); // MS button
          b3.setBounds(130, 100, 55, 50);
JButton b4 = new JButton (new ImageIcon ("mplus.gif")); // M+ button
          b4.setBounds(185, 100, 55, 50);
          JButton b5 = new JButton (new ImageIcon ("seven.gif")); // 7 button
          b5.setBounds(20, 170, 55, 50);
          JButton b6 = new JButton (new ImageIcon ("eight.gif")); // 8 button
          b6.setBounds(75, 170, 55, 50);
          JButton b7 = new JButton (new ImageIcon ("nine.gif")); // 9 button
          b7.setBounds(130, 170, 55, 50);
JButton b8 = new JButton (new ImageIcon ("div.gif")); // divide button
          b8.setBounds(185, 170, 55, 50);
          JButton b9 = new JButton (new ImageIcon ("four.gif")); // 4 button
          b9.setBounds(20, 220, 55, 50);
          JButton b10 = new JButton (new ImageIcon ("five.gif")); // 5 button
          b10.setBounds(75, 220, 55, 50);
          JButton b11 = new JButton (new ImageIcon ("six.gif")); // 6 button
          b11.setBounds(130, 220, 55, 50);
          JButton b12 = new JButton (new ImageIcon ("times.gif")); // times button
          b12.setBounds(185, 220, 55, 50);
JButton b13 = new JButton (new ImageIcon ("one.gif")); // 1 button
          b13.setBounds(20, 270, 55, 50);
          JButton b14 = new JButton (new ImageIcon ("two.gif")); // 2 button
          b14.setBounds(75, 270, 55, 50);
          JButton b15 = new JButton (new ImageIcon ("three.gif")); // 3 button
          b15.setBounds(130, 270, 55, 50);
          JButton b16 = new JButton (new ImageIcon ("minus.gif")); // minus button
          b16.setBounds(185, 270, 55, 50);
          JButton b17 = new JButton (new ImageIcon ("zero.gif")); // 0 button
          b17.setBounds(20, 320, 55, 50);
          JButton b18 = new JButton (new ImageIcon ("neg.gif")); // negitive button
          b18.setBounds(75, 320, 55, 50);
          JButton b19 = new JButton (new ImageIcon ("dot.gif")); // decimal button
          b19.setBounds(130, 320, 55, 50);
          JButton b20 = new JButton (new ImageIcon ("add.gif")); // addition button
          b20.setBounds(185, 320, 55, 50);
          JButton b21 = new JButton (new ImageIcon ("left.gif")); // left bracket button
          b21.setBounds(20, 375, 110, 35);
          JButton b22 = new JButton (new ImageIcon ("right.gif")); // right bracket button
          b22.setBounds(130, 375, 110, 35);
          JButton b23 = new JButton (new ImageIcon ("equals.gif")); // equals button
          b23.setBounds(20, 415, 220, 35);
JButton b24 = new JButton (new ImageIcon ("clear.gif")); // clear button
          b24.setBounds(20, 460, 55, 50);
          JButton b25 = new JButton (new ImageIcon ("ce.gif")); // ce button
          b25.setBounds(75, 460, 55, 50);
          JButton b26 = new JButton (new ImageIcon ("sqrt.gif")); // sqrt button
          b26.setBounds(130, 460, 55, 50);
          JButton b27 = new JButton (new ImageIcon ("percent.gif")); // % button
          b27.setBounds(185, 460, 55, 50);
          //------------------- adding everything on the pane -------------------
          Container contentPane = getContentPane();
          contentPane.setLayout(null);
          // the default layout is BorderLayout
          contentPane.add(b1); // adds buttons
          contentPane.add(b2);
          contentPane.add(b3);
          contentPane.add(b4);
          contentPane.add(b5);
          contentPane.add(b6);
          contentPane.add(b7);
          contentPane.add(b8);
          contentPane.add(b9);
          contentPane.add(b10);
          contentPane.add(b11);
          contentPane.add(b12);
          contentPane.add(b13);
          contentPane.add(b14);
          contentPane.add(b15);
          contentPane.add(b16);
          contentPane.add(b17);
          contentPane.add(b18);
          contentPane.add(b19);
          contentPane.add(b20);
          contentPane.add(b21);
          contentPane.add(b22);
          contentPane.add(b23);
          contentPane.add(b24);
          contentPane.add(b25);
          contentPane.add(b26);
          contentPane.add(b27);
          contentPane.add(answer); // adds answer label
          contentPane.add(expression); // adds expression lable
          menuBar.add(menu); // adds menu
          menu.add(menuItem); // adds menu item "Help"
          menu.add(menuItem1); // adds menu item "Splash Page"
//------------ button functions ---------------------------------------
          b1.addActionListener(new ActionListener()          // MR
          {     public void actionPerformed(ActionEvent e)
               {     String TempMemory="";
                    answer.setText(TempMemory.valueOf(memory)); }});
          b2.addActionListener(new ActionListener()          //Mc
          {     public void actionPerformed(ActionEvent e)
               {     memory=0; }});
          b3.addActionListener(new ActionListener()          //M-
          {     public void actionPerformed(ActionEvent e)
               {     Double DblTemp=new Double(answer.getText());
                    double dblTemp=DblTemp.doubleValue();
                    memory=memory-dblTemp; }});
          b4.addActionListener(new ActionListener()          //M+
          {     public void actionPerformed(ActionEvent e)
               {     Double DblTemp=new Double(answer.getText());
                    double dblTemp=DblTemp.doubleValue();
                    memory=memory+dblTemp; }});
b5.addActionListener(new ActionListener() // Seven
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"7";
                    expression.setText(exp); }});
          b5.addKeyListener(this);
          b6.addActionListener(new ActionListener() // Eight
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"8";
                    expression.setText(exp); }});
          b6.addKeyListener(this);
          b7.addActionListener(new ActionListener() // Nine
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"9";
                    expression.setText(exp); }});
          b7.addKeyListener(this);
          b8.addActionListener(new ActionListener()          // Divide
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"/";
                    expression.setText(exp); }});
          b8.addKeyListener(this);
          b9.addActionListener(new ActionListener() // Four
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"4";
                    expression.setText(exp); }});
          b9.addKeyListener(this);
          b10.addActionListener(new ActionListener() // Five
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"5";
                    expression.setText(exp); }});
          b10.addKeyListener(this);
          b11.addActionListener(new ActionListener() // Six
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"6";
                    expression.setText(exp); }});
          b11.addKeyListener(this);
          b12.addActionListener(new ActionListener()     // Times
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"*";
                    expression.setText(exp); }});
          b12.addKeyListener(this);
          b13.addActionListener(new ActionListener() // One
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"1";
                    expression.setText(exp); }});
          b13.addKeyListener(this);
          b14.addActionListener(new ActionListener() // Two
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"2";
                    expression.setText(exp); }});
          b14.addKeyListener(this);
          b15.addActionListener(new ActionListener() // Three
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"3";
                    expression.setText(exp); }});
          b15.addKeyListener(this);
          b16.addActionListener(new ActionListener()          // Minus
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"-";
                    expression.setText(exp); }});
          b16.addKeyListener(this);
          b17.addActionListener(new ActionListener() // Zero
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"0";
                    expression.setText(exp); }});
          b17.addKeyListener(this);
          b18.addActionListener(new ActionListener() // negative
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"-";
                    expression.setText(exp); }});
          b18.addKeyListener(this);
          b19.addActionListener(new ActionListener()          // Decimal
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+".";
                    expression.setText(exp); }});
          b19.addKeyListener(this);
          b20.addActionListener(new ActionListener()          // Addition
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"+";
                    expression.setText(exp); }});
          b20.addKeyListener(this);
          b21.addActionListener(new ActionListener()     // Left Bracket
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+"(";
                    expression.setText(exp); }});
          b21.addKeyListener(this);
          b22.addActionListener(new ActionListener()          // Right Bracket
          {     public void actionPerformed(ActionEvent e)
               {     exp=exp+")";
                    expression.setText(exp); }});
          b22.addKeyListener(this);
          b23.addActionListener(new ActionListener() // Equals
          {     public void actionPerformed(ActionEvent e)
               {     LkList equation = new LkList();
                    equation.ProcessExpress();
                    ans=equation.getAns();
                    answer.setText(ans);
                    exp="";
                    ans="";     }});
          b23.addKeyListener(this);
          b24.addActionListener(new ActionListener()          // Clear
          {     public void actionPerformed(ActionEvent e)
               {     exp="";
                    ans="";
                    expression.setText(exp);
                    answer.setText(ans); }});
          b25.addActionListener(new ActionListener()          // Clear Entry
          {     public void actionPerformed(ActionEvent e)
               {     exp="";
                    ans="";
                    expression.setText(exp);
                    answer.setText(ans); }});
          addWindowListener( new WindowAdapter()
                    {     public void windowClosing(WindowEvent e)
                         {     System.exit(0);
          this.setBounds(10, 10, 270, 600);
          this.show();
     public static void main(String[] args)
     {     new JCal();
public void keyReleased(KeyEvent evt){}
     public void keyTyped(KeyEvent evt) {}
     public void keyPressed(KeyEvent evt)
     {     char x=evt.getKeyChar();
          switch(x)
          {     case '0': exp=exp+"0";
                    expression.setText(exp);
                    break;
               case '1': exp=exp+"1";
                    expression.setText(exp);
                    break;
               case '2': exp=exp+"2";
                    expression.setText(exp);
                    break;
               case '3': exp=exp+"3";
                    expression.setText(exp);
                    break;
               case '4': exp=exp+"4";
                    expression.setText(exp);
                    break;
               case '5': exp=exp+"5";
                    expression.setText(exp);
                    break;
               case '6': exp=exp+"6";
                    expression.setText(exp);
                    break;
               case '7': exp=exp+"7";
                    expression.setText(exp);
                    break;
               case '8': exp=exp+"8";
                    expression.setText(exp);
                    break;
               case '9': exp=exp+"9";
                    expression.setText(exp);
                    break;
               case '+': exp=exp+"+";
                    expression.setText(exp);
                    break;
               case '-': exp=exp+"-";
                    expression.setText(exp);
                    break;
               case '*': exp=exp+"*";
                    expression.setText(exp);
                    break;
               case '/': exp=exp+"/";
                    expression.setText(exp);
                    break;
               case '.': exp=exp+".";
                    expression.setText(exp);
                    break;
               case '(': exp=exp+"(";
                    expression.setText(exp);
                    break;
               case ')': exp=exp+")";
                    expression.setText(exp);
                    break;
               default: break;
// ================================= equation =============================
class Equation
{     private double nbr1;
     private double nbr2;
     private char op;
     private double answer;
     private String StrNum1="";
     private String StrNum2="";
     private String StrOper="";
     private String StrAns="";
     //Constructor
     Equation(String number1, String number2, String operator)
     {     StrNum1 = number1;
          StrNum2 = number2;
          StrOper = operator;
          convert();
     public double getNum1() {return nbr1;}
     public double getNum2() {return nbr2;}
     public char getOp() {return op;}
     private void convert()
     {     Double temp=new Double(StrNum1);
          nbr1=temp.doubleValue();
          temp=new Double(StrNum2);
          nbr2=temp.doubleValue();
          op=StrOper.charAt(0);
     private void convertAnswer()
     {     StrAns=StrAns.valueOf(answer);
     public String toString()
     {     return StrAns;
     public void calculate()
     {     switch (op)
          {     case '+': answer=nbr1+nbr2;
                    break;
               case '-': answer=nbr1-nbr2;
                    break;
               case '*': answer=nbr1*nbr2;
                    break;
               case '/': answer=nbr1/nbr2;
                    break;
          convertAnswer();
// =============================== linked list ================================
class LkList
{  char[] operator = {'+','-','*','/','(',')'}; // operators used
LinkedList Express = new LinkedList(); // Linked list of expression
String StrExp = null;
String oper = ""; // operator
String number1 = ""; // first number used in expression
String number2 = ""; // second number used in expression
String answer = ""; // answer of expression
Exp TempExp; // Temporary expression
String Temp;
// Constructor
LkList (String e)
{ StrExp = e;
     formList (); // expression turn into liked list nodes
     trimList (); // remove spaces from linked list expression
public String toString()
     { return Express.toString();
public LinkedList getList();
     { return Express;
public String getAns()
     { return Express.get(0).toString();
public void ProcessExpress() // removing brackets
     {  removeBrack();
private void formList()
{  int j = 0;
boolean lastOper = true;
     for (j = 0 ; j < Express.length(); j++ )
{  if (!(belongTo(operator, StrExp.charAt (j))))
          {  Temp = Temp + StrExp.charAt (j);
     lastOperator = false;
     if (belongTo(operator, StrExp.charAt (j)))
     {   if ((StrExp.charAt (j) =='-') && (lastOperator))
          {   Temp = "-";
     lastoperator = false;
          else
          {   Express.add (Temp);
          Temp = "";
               Temp = Temp + StrExp.charAt (j);
               Express.add (Temp);
               Temp = "";
               if (StrExp.charAt (j) == ')')
               {  lastOperator = false;
               else
               {   lastOperator = true;
     Express.add (Temp);
     Temp = "";
private void trimlist ()
{   int sp = 0;
while ((sp !=-1))
{  sp = Express.indexOf ("");
     if (sp !=-1)
     {  Express.remove (sp);
private static boolean belongTo (char[] ar, char c)
{  for (int k = 0; k < ar.length; k++)
     {  if (c == ar[k]) return true;
return false;
private boolean findBrack ()
{  if (Express.contains (")"))
{  return true;
return false;
private void removePoints (int pt1, int pt2 )
{  int range = (pt2 - pt1);
for (int j = pt2; j >= pt1; j--)
{  Express.remove (j);
private void processOperator (String Oper)
{  int point =-1;
     while (Express.contains (Oper))
     {  point = Express.indexOf (Oper);
     oper = Express.get(point).toString();
          number1 = Express.get(point-1).toString();
          number2 = Express.get(point+1).toString();
          TempExp = new Exp (number1, number2, oper);
          TempExp.calculate();
          answer = Temp.toString();
          Express.add(point-1, point+1);
          removePoints (point-1, point+1);
point =-1;
private void removeBrack()
{  int opBrack = 0;
int clBrack = 1;
     int j = 0;
     String Temp = "";
     while (findBrack())
     {  clBrack = Express.indexOf (")");
     j = clBrack;
          do
          {  Temp = Express.get(j).toString();
          if (Temp.charAT(0) =='(')
          {   opBrack = j;
               j--;
          while (opBrack < 0);
          number1 = Express.get(opBrack +1).toString();
number2 = Express.get(clBrack -1).toString();
          oper = Express.get(opBrack+2).toString();
          TempExp = new Exp (number1, number2, oper)
          TempExp.calculate();
          answer = TempExp.toString();
          Express.add(clBrack+1, answer);
          removePoints(opBrack, clBrack);
          opBrack=-1;
          clBrack=0;
private void removeDivide()                         
     {     processOperator("/");                    
          remMult();                         
     private void removeTimes()                         
     {     processOperator("*");                         
          remAdd();                         
     private void removeAdd()                         
     {     processOperator("+");                         
          remSub();                         
     private void removeSub()                         
     {     processOperator("-");
// ================================= help menu ============================
class JHelp extends JFrame
{     JTextArea textarea;
     public JHelp()
     {     super ("Help");
          Container contentPane = getContentPane();
     /*     JPanel textPan1 = new JPanel (new BorderLayout());
          textarea = new JTextArea ("How to use Nicks Calculator");
          textarea.setWrapStyleWord(false);
          JScrollPane textAreaPane1 = new JScrollPane (textarea);
          textPan1.add (textarea, BorderLayout.CENTER);
          contentPane.add(textPan1);
          textarea.setEnabled(false); */
          JLabel lab=new JLabel(new ImageIcon("helpmenu.jpg"));
          contentPane.add(lab, BorderLayout.CENTER);
          setBounds(400,200,400,400);
          this.show();
// ================================ Splash Page =============================
class JSplash extends JFrame
{     public JSplash()
{   super ("Splash Page");
          Container contentPane=getContentPane();
          JLabel lab=new JLabel(new ImageIcon("nick.jpg"));
          contentPane.add(lab, BorderLayout.CENTER);
          setBounds(400,200,250,320);
          this.show();

Answer 1

Spot the difference:
public LinkedList getList();
public LinkedList getList()
Notice the semi-colon. Thats the problem