code: public void write(File file) throws IOException {
  		Assert.state(this.pid != null, "No PID available");
  		createParentFolder(file);
  		if (file.exists()) {
  			assertCanOverwrite(file);
  		}
  		try (FileWriter writer = new FileWriter(file)) {
  			writer.append(this.pid);
  		}
  	}
docs: Write the PID to the specified file.
  @param file the PID file
  @throws IllegalStateException if no PID is available.
  @throws IOException if the file cannot be written