Javafx Program for encrypting file from user. Need help to fix/improve the following code:

public class Encrypting extends Application{

double paneWidth = 400;

double paneHeight = 100;

TextField tfEncryptInput;

TextField tfEncryptOutput;

@Override

public void start(Stage primaryStage) throws IOException,EOFException {

// TODO Auto-generated method stub

tfEncryptInput = new TextField();

tfEncryptInput.setPromptText("File to encrypt");

tfEncryptInput.getText();

tfEncryptOutput = new TextField();

tfEncryptOutput.setPromptText("Save encrypted file to");

// Create encrypt button

Button btCrypt = new Button("Encrypt");

// New pane, add tf`s and bt

GridPane pane = new GridPane();

pane.setAlignment(Pos.CENTER);

pane.add(tfEncryptInput, 1, 0);

pane.add(tfEncryptOutput, 2, 0);

pane.add(btCrypt,1,2);

// Create a scene and place it in the stage

Scene scene = new Scene(pane, paneWidth, paneHeight);

primaryStage.setTitle("Encrypt file"); // Set the stage title

primaryStage.setScene(scene); // Place the scene in the stage

primaryStage.show(); // Display the stage

btCrypt.setOnAction(new EventHandler() {

public void handle(ActionEvent event) {

try {BufferedInputStream input = new BufferedInputStream( // Input file from user

new FileInputStream(new File(tfEncryptInput.getText())));

BufferedOutputStream output = new BufferedOutputStream( // Outputfile from user

new FileOutputStream(new File(tfEncryptInput.getText())));

int value;

while ((value=input.read())!=-1) {

output.write(value+5);

}

input.close();

output.close();

} catch (IOException e) {//Exception

}

}

});