Ho provato a salvare le proprietà e restituirle ma dove ho sbagliato? thanks

codice:
class App {
			  public void main(String[] args) {


				Properties prop = new Properties();
				Properties prop1 = new Properties();
				Properties prop2 = new Properties();
				Properties prop3 = new Properties();
				OutputStream output = null;


				try {


					output = new FileOutputStream("config.properties");


					// Imposta il valore di proprietà
					prop.getProperty(textCLIENTE.getText());
					prop1.getProperty(textNUM.getText());
					prop2.getProperty(textMAIL.getText());
					prop3.getProperty(textVIA.getText());


					// Salvare le proprietà di proiettare cartella principale
					prop.store(output, null);
					prop1.store(output, null);
					prop2.store(output, null);
					prop3.store(output, null);


				} catch (IOException io) {
					io.printStackTrace();
				} finally {
					if (output != null) {
						try {
							output.close();
						} catch (IOException e) {
							e.printStackTrace();
						}
					}


				}
			  }
			}	
		
		
		class App1 {


			  public void main(String[] args) {
				App1 app = new App1();
				app.printThemAll();
			  }


			  private void printThemAll() {


				Properties prop = new Properties();
				InputStream input = null;


				try {


					String filename = "config.properties";
					input = getClass().getClassLoader().getResourceAsStream(filename);
					if (input == null) {
						System.out.println("Sorry, unable to find " + filename);
						return;
					}


					prop.load(input);


					Enumeration<?> e = prop.propertyNames();
					while (e.hasMoreElements()) {
						String key = (String) e.nextElement();
						String value = prop.getProperty(key);
						System.out.println("Key : " + key + ", Value : " + value);
					}


				} catch (IOException ex) {
					ex.printStackTrace();
				} finally {
					if (input != null) {
						try {
							input.close();
						} catch (IOException e) {
							e.printStackTrace();
						}
					}
				}


			  }


			}