Java to parse output from Brakeman

BrakemanScanner.java

/* Parse tab-separated output from Brakeman
 * Use: 
 *  brakeman -o example.tabs
 *  java BrakemanScanner example.tabs
 */

import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.io.RandomAccessFile;

public class BrakemanScanner {

    private static Pattern pattern = Pattern.compile("^([^\t]+?)\t(\\d+)\t([\\w\\s]+?)\t(\\w+)\t([\\w\\s]+?)\t(High|Medium|Weak)", Pattern.MULTILINE);

    public static void main(String[] argv) {
        new BrakemanScanner().scan(argv[0]);
    }   

    public void scan(String filename) {
        System.err.println("Pattern: "  + this.pattern);
        Matcher m = this.pattern.matcher(readFile(filename));

        while(m.find()) {
            System.out.println("File: " + m.group(1));
            System.out.println("Line number: " + m.group(2));
            System.out.println("Type: " + m.group(3));
            System.out.println("Category: " + m.group(4));
            System.out.println("Message: " + m.group(5));
            System.out.println("Confidence: " + m.group(6));
            System.out.println("----------------------------");
        }       
    }   

    public String readFile(String filename) {
        try {   
            RandomAccessFile f = new RandomAccessFile(filename, "r");
            byte[] b = new byte[(int)f.length()];
            f.readFully(b);
            System.err.println("Read file of length " + b.length);
            return new String(b);
        }       
        catch(Exception e) {
            System.err.println(e);
            return null;
        }       
    }   
}