Is this a memory leak or a false positive?

This is my code:

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.Scanner;

public class temp {
    public static void main(String[] args) throws FileNotFoundException {
        BufferedReader a = new BufferedReader(new FileReader("a"));
        Scanner scanner = new Scanner(a).useDelimiter(",");
        scanner.close();
    }
}

I get a warning at new Scanner(a) that says (I'm compiling with jdk1.7.0_05.):

Resource leak: '<unassigned Closeable value>' is never closed.

Am I doing something wrong, or is this just a false warning?