annotations reflection vaadin

Listing annotated classes in Java EE

The Java EE platform is huge, and I must confess I'm not aware of every one of its API. This is also true of the Spring framework, even though I think I know more of Spring than of Java EE. Lately, I was working on the version 10 of the Vaadin framework also known as Vaadin Flow. This version introduces routes. When a path is requested, the Vaadin Servlet displays the component. Routes are created by annotating specific components with the @Route annotation. Thus, Vaadin needs to list all annotat

API JDK design Cloneable

Cloneable, a Java design gotcha

Some time ago, I described a couple of surprising design choices in the JDK functional interfaces API. Lately, during a lesson, a student of mine proposed to shallow-copy an ArrayList by using the clone() method: I thought this is another API gotcha worth writing about. Cloning an object means a new object is created with the same state as the original one. As per the JavaDoc: Creates and returns a copy of this object. The precise meaning of 'copy' may depend on the class of the object.

Clojure arrow threading

Learning Clojure: the arrow and doto macros

For me, learning a new language is like getting into the sea: one toe at a time. Last week was the occasion to get familiar with the spec library. This week, we will have a look at some powerful macros. The problem When you’re not used to Clojure, parentheses may sometimes impair the readability of code. (- 25 (+ 5 (* 3 (- 5 (/ 12 4))))) The Kotlin equivalent of the above snippet would be: 25 - (5 + (3 * (5 - (12 / 4)))) Obviously, it’s related neither to Clojure nor

Clojure specifications type

Learning Clojure: coping with dynamic typing

My new position requires me to get familiar with the Clojure language. In intend to document what I learn in a series of posts, to serve as my personal reference notes. As a side-effect, I hope it will also be beneficial to others who want to take the same path. There are already a multitude of great tutorials available: hence, each post will focus on a specific theme, that is specific to Clojure considering that most of my experience comes from OOP. As a newcomer to Clojure, a big issue of min

API design interface default method Java 8

Default methods in Java 8, and what it changes in API design

Java 8 introduced default methods in interfaces. This post describes what they are, and how they can change the design of APIs. A nominal design Earlier, in Java, interfaces could only have contracts - method signatures with no implementation. In order to add some implementation, a class was required, whether abstract or not. Hence, traditional API design then followed this hierarchy: The root interface defines the contractAn intermediate class implements common behavior i.e. BarIf