With a scanner search on ArrayList the content and print the line

Question

I have a text file (.txt) and I'm stuck here. I user a BufferReader to read all file and save in a ArrayList then put the ArrayList into a String to remove the , [ ] Now I need to find the word of the scanner ex: (1001) in the ArrayList that the user want, and print the line of this word and the 4 lines after that. After that, edit this 4 lines and save the ArrayList to a file.

Or have something more simple without using ArrayLists? Thank you.

System.out.println("Digite o ID ou 1 para sair: ");
                Scanner sOPFicheiro = new Scanner(System.in);
                opFicheiro = sOPFicheiro.nextInt();
                     if (opFicheiro == 1){
                         System.out.println("A voltar ao menu anterior...");
                         Thread.sleep(1000);
                         editarFicheiro();
                     } else {
                            //Envia para um ArrayList o ficheiro Formandos
                            ArrayList<String> textoFormandos = new ArrayList<String>();
                            BufferedReader ler = new BufferedReader(new FileReader(FichFormandos));
                            String linha;
                        while ((linha = ler.readLine()) != null) {
                            textoFormandos.add(linha + "\n");
                        }
                        ler.close();
                              
                              //Remove , [ ] do ArrayList para enviar para o ficheiro
                              String textoFormandos2 = Arrays.toString(textoFormandos.toArray()).replace("[", "").replace("]", "").replace(",", "");
                         
                     }

File: Txt File

Answer 1

Instead of using an ArrayList use a StringBuilder :

    StringBuilder textoFormandos = new StringBuilder();
    while ...
        textoFormandos.append(linha + "\n");
    ...
    String textoFormandos2 = textoFormandos.toString();

This way you won't need to remove anything. For the rest you need to clear the requirements.