java.util.Optional means getOrElseThrowNoSuchElementException

java.util.Optional 
...means getOrElseThrowNoSuchElementException

An example:

    @Autowired
    private SimulationDao simulationDao;

@GetMapping(value = "/simulation/{id}")
public Simulation getSimulation(@PathVariable("id") Long id) {
        Simulation simulation = null;
        try {
            Optional simulationOptional =
                    Optional.ofNullable(simulationDao.findById(BigInteger.valueOf(id)));
            if (simulationOptional.isPresent()) {
                simulation = simulationOptional.get();
            }
        } catch (Exception ex) {
   (...)

https://javarevisited.blogspot.com/2017/04/10-examples-of-optional-in-java-8.html

https://mkyong.com/java8/java-8-optional-in-depth/

https://dzone.com/articles/using-optional-correctly-is-not-optional

https://www.geeksforgeeks.org/optional-ofnullable-method-in-java-with-examples/

https://www.baeldung.com/java-optional

https://klolo.github.io/blog/2017/08/05/jak-uzywac-optional/

https://codecouple.pl/2016/03/09/pozbadz-sie-null-pointerow-java-util-optional/

Source: Internet