try closing the BufferedWriter object after you finish writing:
public void WriteOutput( ArrayList<detailTom> tomData1){ try{ BufferedWriter writer = new BufferedWriter(new FileWriter("G:/sampleOutput.txt")); for (detailTom detail : tomData1) { writer.write(detail.toString()); }
writer.close();
} catch (IOException ex) { Logger.getLogger(MyInterface.class.getName()).log(Level.SEVERE, null,ex); } }