Objective c undefined reference to objc class

public class StudentListings{

 
     private String name;   // key field 

 
     private int ID; 

 
     private double GPA; 
 
     private int next; 
 
     private int size;
 
     private StudentListing[] data; 
 
 
   public StudentListings(){
 
       this.name= name; 
       this.id= ID; 
       this.gpa=GPA; 
   } 
 
   public StudentListings(){ 
 
    next=0; 
    data= new StudentListings[Size]; 
    size= Size; 
 
   } // end of constructor 
  ...

Hi,

I'm creating a program were logs files in a certain directory are presented in a table format.

My issue here is, I created a filter option in which the ...

Hi every one .
i need code for how i set the connection i.e when i execute the project .exe it show me a form in which there is Database ...