If we pass a file path and a word and the replace word to a method then it will replace all the word in that file with replace word.
/************************ * Code to replace all word in a test file ************************/ import java.io.*; public class repalceWord { /*Repalces words in a file*/ public static void contentReplace(String filepath,String word,String replaceword) { //String filepath="D:/test.txt"; //String word="something"; //String replaceword="evertthing"; String data=""; File file=new File(filepath); try{ FileInputStream fis = new FileInputStream(file);/*creates a new file input stream */ InputStreamReader is = new InputStreamReader(fis);/*Creates a new file input stream*/ BufferedReader br = new BufferedReader(is);/*creates a buffer reader*/ String strLine=""; while ((strLine = br.readLine()) != null)/*checks if their are any lines in a file { if(strLine.contains(word)){ /*checks if the file contains such a word*/ data+=strLine.replaceAll(word, replaceword)+"n";/*It replaces all the words in the file*/ }else{ data+=strLine+"n";/*If no such word it moves to next line*/ } } System.out.println(data); br.close(); is.close(); fis.close(); FileOutputStream fileOutputStream=new FileOutputStream(filepath,false);/*creates a new file output stream */ Writer outx=new OutputStreamWriter(fileOutputStream);/*creates a Writer for the file output stream */ if(data.contains("n")){ String[] list=data.split("n");/*split the data*/ for(int i=0;i<list.length;i++){ outx.write(list[i]); outx.append("n"); } }else{ outx.write(data); outx.append("n"); } outx.close(); fileOutputStream.close(); }catch(Exception e){ e.printStackTrace(); } } }