Hi, I want the input to accept only: digits, operators and space. How could I do?
I mean:

When I type: 8 – 9 a b c ! ?
It should throw exception.

When I type: 8 – 9 + 20 * 1 / 5
It should end in success.

I tried but could not
Code:
package assignments;

import java.util.Scanner;

public class RegexTest {

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		String s = scanner.next();
		
		// try to input: 8 - 9 + 20 * 1 /   5		
		try {
			if(s.matches("[^ \\d \\+ \\- \\* \\/]+"))
				throw new Exception();
		} catch (Exception e) {			
			System.err.println("Recycle bin: \"I\'m here\"");
		}					
	}
}