Getting Stomp working using Spring was very easy. It didn’t seem that easy to me because I tested my implementation with an integration test which seemed to fail at least as much as it succeeded. In this post I will take you through my journey of getting a stable integration test on Spring Websockets.

Congratulations! Someone has made the wise decision to hire you as the new technical lead. It is an exciting time. You start in a new environment, will be working with a new team and maybe even have to learn new technologies along the way. This can be quite challenging. In the first article I wrote about introducing change. In this second article I want to share my personal views on shaping great teams. As team lead, there are certain values that are just part of me and they way I think about leadership. Fortunately, in JDriven I found a company that matches my values step by step. These values are #commit, #develop and #share. In this article I want to go into some of the values that I consider important to create a great team.

With the release of Java 9, and the introduction of Project Jigsaw (the Java Platform Module System), we no longer have the need for a full-blown JRE to run our Java applications. It is now possible to construct a stripped-down Java Runtime, containing the minimum set of required modules. This allows us to create slim Docker containers without excess baggage. The source code belonging to this blog post can be found at: https://github.com/rlippolis/java9-runtime-image

Congratulations! Someone has made the wise decision to hire you as the new technical lead. It is an exciting time. You start in a new environment, will be working with a new team and maybe even have to learn new technologies along the way. This can be quite challenging. In this two-part article I want to share my personal views regarding Introducing change and shaping teams as a technical lead.

With the Asciidoctor diagram extension we can include diagrams that are written in plain text. For example PlantUML or Ditaa diagrams. The extension offers a block processor where we include the diagram definitions in our Asciidoctor document. But there is also a block macro processor. With the block macro processor we can refer to an external file. The file is processed and the resulting image is in our output document.

In the following example we see how to use the block macro for a Ditaa diagram:

In our Groovy scripts we can use the @Grab annotation. With this annotation we define dependencies for our script and they will be automatically downloaded and added to the class path when we run our script. When we use IntelliJ IDEA we can use a nice intention that is part of the IntelliJ IDEA Groovy support to download the dependencies from our IDE editor. IDEA downloads the dependencies and add it to the project module dependencies. This is useful, because this will also adds code completion for the classes in the dependency to our editor.

Let’s see this with a little example. We have the following Groovy script in our Groovy project in IntelliJ IDEA:

Just as we are over the crest of the microservice hype and can finally see how this architectural tool might (or might not) solve our problems the next hype is already here: serverless programming! In this first blog post I’m going to explain what serverless is, what it isn’t, and how it can change the way we create software. In the next posts I’m going to show a few simple examples using a well known 'serverless' platform: AWS Lambda. Originally posted here .

Maven can be set up to use a private repository, i.e. Nexus. Usually the repository runs on http and there isn’t any problem to connect to the repository, but when the repository runs on https maven isn’t able to connect to it automatically. The solution to this is to add the server’s certificate to the default Java keystore. When connecting to your https-repository fails, Maven will show you an exception like

To resolve this, download the server’s certificate and add it to the default Java keystore. The easiest way to download the certificate is with the Java provided keytool. The following command is an example to download the certificate to a .pem file

PlantUML has a built-in icon set we can use in our diagram definitions. The icon set is open source icon set OpenIconic. We refer to an icon using the syntax <&iconName>.We can use an icon everywhere where we can use text in our diagrams.

In the following example we use different icons in different places:

PlantUML supports sprites to be used in diagrams. A sprite is text encoded monochrome graphic we can reference using the syntax <$spriteName>. The sprite is defined using hexadecimal values. We can define a set of hexadecimal values to create our sprite, but we can also generate the correct values from for example a PNG image.

We start with a simple example where we create a small triangle using hexadecimal values:

In a previous post we learned how to use a together block to keep elements together. We can also layout elements in a different way: using hidden lines. We define our elements and by using the keyword [hidden] in our line definition the elements are layout as if there was a line, but we don’t see it. This gives us great flexibility on how we layout our elements.

In the following sample we first have a PlantUML definition where we rely on the default layout:

We have a lot of ways to customize our PlantUML diagrams. We can change the colors and we can even set gradients as color. A gradient has two colors and a direction. The direction of the gradient is set by the separator between the two colors. We can use the following separators to set the gradient direction: