Java program codes: queue implementation in java

import java.io.*;
import java.util.*;

public class QueueImplement{
LinkedList<Integer> list;
String str;
int num;
public static void main(String[] args){
QueueImplement q = new QueueImplement();
}
public QueueImplement(){
try{
list = new LinkedList<Integer>();
InputStreamReader ir = new InputStreamReader(System.in);
BufferedReader bf = new BufferedReader(ir);
System.out.println("Enter number of elements : ");
str = bf.readLine();
if((num = Integer.parseInt(str)) == 0){
System.out.println("You have entered either zero/null.");
System.exit(0);
}
else{
System.out.println("Enter elements : ");
for(int i = 0; i < num; i++){
str = bf.readLine();
int n = Integer.parseInt(str);
list.add(n);
}
}
System.out.println("First element :" + list.removeFirst());
System.out.println("Last element :" + list.removeLast());
System.out.println("Rest elements in the list :");
while(!list.isEmpty()){
System.out.print(list.remove() + "\t");
}
}
catch(IOException e){
System.out.println(e.getMessage() + " is not a legal entry.");
System.exit(0);
}
}
}