Question

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

class Read
{
    public static void main(String args[])
    {
        try {
        Scanner scan = new Scanner(new java.io.File("textfile.txt"));
        } catch (FileNotFoundException e){
        }        
        while(scan.hasNext()){
        String line = scan.nextLine();
        String[] elements = line.split(",");
        }
    }
}

Why do I get

error: cannot find symbol
        while(scan.hasNext()){
              ^
  symbol:   variable scan

?

Answer 1

The issue is with the scope. You can declare the Scanner object outside of the try...catch block, and instantiate it inside of it.

It’s definitely also the case that you would want to put all of your I/O operations that depend on the Scanner being instantiated inside of the try...catch too, or you’ll run into issues later.

Example:

public static void main(String[] args) {
    Scanner scan = null;
    try {
        scan = new Scanner(new File("textfile.txt"));
        // other I/O operations here including anything that uses scan
    } catch (FileNotFoundException e) {
        System.out.println("helpful error message", e);
    }
 }