NestedJavaNulls.java

// java < 8
if (document != null && document.getOrder() != null && document.getOrder().getAddress() != null && document.getOrder().getAddress().getStreet() != null) {
  // boom
)

// java >= 8
Optional<Street> street = resolve(() -> document.getOrder().getAddress().getStreet());

if (street.isPresent() {
  street.get();
} else {
 // boom
}

public static <T> Optional<T> resolve(Supplier<T> resolver) {
  try {
    T result = resolver.get();
    return Optional.ofNullable(result);
  }
  catch (NullPointerException e) {
    return Optional.empty();
  }
}

thanks to http://winterbe.com/posts/2015/03/15/avoid-null-checks-in-java/