import java.io.BufferedReader;

import java.io.FileReader;

import java.io.File;

import java.io.FileWriter;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.PrintWriter;

public class FileUtil {

  public void removeLineFromFile(String file, String lineToRemove) {

    try {

      File inFile = new File(file);

      

      if (!inFile.isFile()) {

        System.out.println("Parameter is not an existing file");

        return;

      }

       

      //Construct the new file that will later be renamed to the original filename. 

      File tempFile = new File(inFile.getAbsolutePath() + ".tmp");

      

      BufferedReader br = new BufferedReader(new FileReader(file));

      PrintWriter pw = new PrintWriter(new FileWriter(tempFile));

      

      String line = null;

      //Read from the original file and write to the new 

      //unless content matches data to be removed.

      while ((line = br.readLine()) != null) {

        

        if (!line.trim().equals(lineToRemove)) {

          pw.println(line);

          pw.flush();

        }

      }

      pw.close();

      br.close();

      

      //Delete the original file

      if (!inFile.delete()) {

        System.out.println("Could not delete file");

        return;

      } 

      

      //Rename the new file to the filename the original file had.

      if (!tempFile.renameTo(inFile))

        System.out.println("Could not rename file");

      

    }

    catch (FileNotFoundException ex) {

      ex.printStackTrace();

    }

    catch (IOException ex) {

      ex.printStackTrace();

    }

  }

  public static void main(String[] args) {

    FileUtil util = new FileUtil();

    util.removeLineFromFile("test.txt", "bbbbb");

  }

}

 

The file test.txt now looks like this:

aaaaa

ccccc