Having problem with Scanner

[Programmer Paul]

Hi all, I am experencing some strange problems with the new Scanner class. I am running Java 1.5, update 4 on Windows XP. I have the code below, done using JCreator Pro:

 
import java.io.*;
import java.util.*;
 
public class test
{
    public static void main(String[] args) throws IOException 
    {
        
         Scanner sc = new Scanner(new InputStreamReader(System.in));
        
        String line;  // holds each input line
       
        
            System.out.println(sc.next());
            System.out.println(sc.next());
            System.out.println(sc.next());
            
            System.out.println("Intervene");
                               
            newfunc();
        
    }
    
       
     public static void newfunc() throws IOException
    {
         Scanner sc = new Scanner(new InputStreamReader(System.in));
        
        String line;  // holds each input line
                
        System.out.println(sc.next());
        System.out.println(sc.next());
        
    }
 
}

The program works fine, but if I attempt to redirect input from a file, such as:

java test < commands.txt

it will crash with a NoSuchElementException.

Any idea what I am doing wrong?

[Joe Sondow]

The problem has to do with your attempt to open an input stream using System.in, followed by another attempt to open an input stream using System.in without having closed the first stream. Here's a version of your program that doesn't have that problem:

import java.io.*;
import java.util.*;
 
public class test
{
    static Scanner sc = new Scanner(new InputStreamReader(System.in));
 
    public static void main(String[] args) throws IOException 
    {
        String line;  // holds each input line
        
        System.out.println(sc.next());
        System.out.println(sc.next());
        System.out.println(sc.next());
            
        System.out.println("Intervene");
                               
        newfunc();
    }
       
    public static void newfunc() throws IOException
    {
        String line;  // holds each input line
                
        System.out.println(sc.next());
        System.out.println(sc.next());   
    }
}