optional

Java has long been infamous for its NullPointerException. The reason for the NPE is calling a method or accessing an attribute of an object that has not been initialized. var value = foo.getBar().getBaz().toLowerCase(); Running this snippet may result in something like the following: Exception in thread 'main' java.lang.NullPointerException at ch.frankel.blog.NpeSample.main(NpeSample.java:10) At this point, you have no clue which part is null in the call chain: foo, or the value ret

This week, I learned about a nifty 'new' feature of Optional that I want to share in this post. It’s available since Java 9, so its novelty is relative. Let’s start with the following sequence to compute the total price of an order: public BigDecimal getOrderPrice(Long orderId) { List<OrderLine> lines = orderRepository.findByOrderId(orderId); BigDecimal price = BigDecimal.ZERO; (1) for (OrderLine line : lines) { price = price.add(line.getPrice());