Why the errors ?

Question

Can someone tell me why I'm getting these errors, I am fairly new to building my own classes.
  if (id.inList())
int i = reg.getIndex();
drop.add((Student)o);
}I am getting 3 errors here, Cannot Find Symbol, but the methods are in the class Addmisions, see Addmisions below
1)
RegistrationTestClass.java:50: cannot find symbol
symbol : method inList()
location: class java.lang.String
if (id.inList())
^
2)
RegistrationTestClass.java:53: cannot find symbol
symbol : method getIndex()
location: class Addmisions
int i = reg.getIndex();
^
3)
RegistrationTestClass.java:55: cannot find symbol
symbol : variable o
location: class RegistrationTestClass
drop.add((Student)o);
^
import java.util.ArrayList;
import java.lang.Object;
public class Addmisions
ArrayList list;            
int index;
Addmisions()               
list = new ArrayList();
void add(Student s)        
list.add(s);
boolean Empty()            
{return list.isEmpty();
int getindex()
return index;
Object removeItem (int i)
return list.remove(i);
boolean inList(String id)
int i = 0;
boolean found = false;
while(i<list.size() && !found)
{ Object o = list.get(i);
  if (o instanceof Student)
   {  Student s = (Student)o;        
    if(s.getID().equals(id))    
       { found = true;}
        else i++;                        
index = i;
return found;
}

Answer 1

Here is the code, below are the errors(only 2 now)
import java.util.*;
import javax.swing.JOptionPane;
public class RegistrationTestClass
public static void main (String[] args)
int a;
a=4;
while (a == 4)
Addmisions reg = new Addmisions();
Addmisions drop = new Addmisions();
String input;
input = JOptionPane.showInputDialog("1 Register Student   2 Drop Student   3 Print Student Info");
a= Integer.parseInt(input);
while (a==1)
  String lname = JOptionPane.showInputDialog("Last Name:");
   String fname = JOptionPane.showInputDialog("First Name:");
     Name n = new Name(lname,fname);
     String str = JOptionPane.showInputDialog("Street:");
     String city = JOptionPane.showInputDialog("City:");
     String sta = JOptionPane.showInputDialog("State:");
     String zip = JOptionPane.showInputDialog("Zip:");
     Address adr = new Address(str,city,sta,zip);
     String id = JOptionPane.showInputDialog("ID number:");
     Student s = new Student(n,adr,id);
     reg.add(s);
         a = 4;
      // Drop
  while (a==2)
   String id = JOptionPane.showInputDialog("Enter ID of Student to Drop:");
if (reg.Empty())
   { JOptionPane.showMessageDialog(null,"There are no Students to Drop", "Addmissions",JOptionPane.INFORMATION_MESSAGE);
a= 4;
else if (reg.inList(id))
int i = reg.getIndex();
drop.add((Student)o);
System.exit(0);
RegistrationTestClass.java:52: cannot find symbol
symbol : method getIndex()
location: class Addmisions
int i = reg.getIndex();
^
RegistrationTestClass.java:54: cannot find symbol
symbol : variable o
location: class RegistrationTestClass
drop.add((Student)o);