Java remove line from text file

package com.zybnet;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

import junit.framework.TestCase;

public class RemoveLine extends TestCase {

    /**
     * @param args args[0] is the filename, args[1] is the line number
     * @throws IOException
     */
    public static void main(String[] args) throws IOException {
        // Use a random access file
        RandomAccessFile file = new RandomAccessFile(args[0], "rw");
        int counter = 0, target = Integer.parseInt(args[1]);
        long offset = 0, length = 0;

        // Find offset and length of target line
        while (file.readLine() != null) {
            counter++;
            if (counter == target)
                break;
            offset = file.getFilePointer();
        }

        length = file.getFilePointer() - offset;

        if (target > counter) {
            file.close();
            throw new IOException("No such line!");
        }

        byte[] buffer = new byte[4096];
        // the file pointer is set at the end of the target line
        int read = -1;
        while ((read = file.read(buffer)) > -1){
            // go back
            file.seek(file.getFilePointer() - read - length);
            file.write(buffer, 0, read);
            // go ahead by length
            file.seek(file.getFilePointer() + length);
        }
        file.setLength(file.length() - length);
        file.close();
    }

    public static void testMain() throws IOException {
        String[] lines = {"Lorem", "Ipsum", "Dolor", "Sit", "Amen"};
        String tmpFile = "/tmp/a";
        int index = 1;
        BufferedWriter out = new BufferedWriter(new FileWriter(tmpFile));
        for (String line : lines) {
            out.write(line);
            out.write("\n");
        }
        out.close();
        main(new String[] {tmpFile, Integer.toString(index)});
        List<String> read = new ArrayList<String>(lines.length);
        String line = null;
        BufferedReader in = new BufferedReader(new FileReader(tmpFile));
        while ((line = in.readLine()) != null) {
            read.add(line);
            System.err.println(line);
        }
        in.close();

        List<String> src = new LinkedList<String>(Arrays.asList(lines)) ;
        src.remove(index - 1);
        assertEquals(src, read);
    }

}