FileWriter || BufferedWriter

/*
 * Created on 14.10.2004
 */
package de.tutorials;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;

/**
 * @author Darimont
 *  
 */
public class Test11 {

    public static void main(String[] args) {
        try {
            RandomAccessFile raf = new RandomAccessFile(
                    new File("c:/Test.fil"), "rw");

            String[] items = { "abc=123\n", "def=456\n", "ghi=789\n" };
            long[] pos = new long[items.length];

            for (int i = 0; i < pos.length; i++) {
                pos[i] = raf.getFilePointer();
                raf.writeBytes(items[i]);
            }
            
            //...
            
            

            raf.seek(pos[1]+"def=".length());//Wir stehen nun vor "456\n"
            //Wir wollen 456 in 999 ändern.
            raf.writeBytes("999");
            raf.close();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

PrintWriter pw = new PrintWriter(new FileWriter("c:\\uhu.txt"));
pw.println(sbStringBuffer.toString()); //StringBuffer ausgeben
pw.close();

File file = new File("c:/temp/test.java");

if (file.exists()){ 
   fileSource.delete();
}