Display TXT in TextArea

I have this code, where I set my Log file in a TextArea. But when I click the Load log button, it shows the log in a line, how do I break line? I would also like the log to display in textArea at runtime, in real time, and not just at the end of the button.

@FXML
    public void carregarLog(ActionEvent event) throws Exception {
        textLog.setText("Logar Jira CAC");
        fieldData.setText(dt);
        String cac = JiraCac.guardarCac;
        fieldCac.setText(cac);

        String arq = "aqui vai pasta e nome do arquivo automacaoTestes.log";
        try{
            BufferedReader in = new BufferedReader(new FileReader(arq));
            System.out.println("Arquivo lido!");
            String str, txt = " \n\r " ;
            while((str = in.readLine()) != null){
                txt += str;
            }
            textLog.setText(txt);
        }
        catch (Exception e) {
            System.err.println("erro");
        }

    }