AdoptOpenJDK 8 NullPointerException sun.awt.FontConfiguration.getVersion(

I recently had to deal with this little bugger as we moved from the OpenJDK 8 package supplied by the Linux distro of choice to AdoptOpenJDK 8. It is important to know that we completely uninstalled OpenJDK, including all its transient dependencies.

(And in due time we’ll uninstall Java 8 and replace that grandpa as well)

As a result, parts of our application didn’t work any longer, resulting in this nice and shiny Java stacktrace.

2019-05-03 08:22:07,345 ERROR [qtp1896708863-35] [PlotChartController] [/][/][/]- error while creating chart image
        at sun.awt.FontConfiguration.getVersion(
        at sun.awt.FontConfiguration.readFontConfigFile(
        at sun.awt.FontConfiguration.init(
        at sun.awt.X11FontManager.createFontConfiguration(
        at sun.font.SunFontManager$
        at Method)
        at sun.font.SunFontManager.<init>(
        at sun.awt.FcFontManager.<init>(
        at sun.awt.X11FontManager.<init>(
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(
        at java.lang.reflect.Constructor.newInstance(
        at java.lang.Class.newInstance(
        at sun.font.FontManagerFactory$
        at Method)
        at sun.font.FontManagerFactory.getInstance(
        at java.awt.Font.getFont2D(
        at java.awt.Font.defaultLineMetrics(
        at java.awt.Font.getLineMetrics(
        at org.jfree.chart.axis.DateAxis.estimateMaximumTickLabelWidth(
        at org.jfree.chart.axis.DateAxis.selectHorizontalAutoTickUnit(
        at org.jfree.chart.axis.DateAxis.selectAutoTickUnit(
        at org.jfree.chart.axis.DateAxis.refreshTicksHorizontal(
        at org.jfree.chart.axis.DateAxis.refreshTicks(
        at org.jfree.chart.axis.ValueAxis.reserveSpace(
        at org.jfree.chart.plot.CombinedDomainXYPlot.calculateAxisSpace(
        at org.jfree.chart.plot.CombinedDomainXYPlot.draw(
        at org.jfree.chart.JFreeChart.draw(
        at org.jfree.chart.JFreeChart.createBufferedImage(
        at org.jfree.chart.JFreeChart.createBufferedImage(
        at org.jfree.chart.ChartUtilities.writeChartAsPNG(

I obviously removed some (a lot) parts to make it more readable and to hide corporate IP 😉 But this is the relevant part.

I found this bug report on Github and for once, plowing through the comments, it helped me. As is mentioned there, the culprit is the missing “fontconfig” package. So, I added another Ansible task to our playbook to provision the server et voila, the problem is gone.

- name: Install fontconfig package
    name: fontconfig
    state: present
      - java

As mentioned earlier, we had wiped all that was relevant to OpenJDK off the system and by doing so, also uninstalled the “fontconfig” package. Otherwise this error wouldn’t have surfaced. But that’s the benefit of starting with a clean slate. This way you know if something is missing and don’t get surprised by errors all of a sudden while, at the same time, it is working on another machine.

Micrometer and Spring (Non-Boot)

Almost all of the tutorials and blog posts I found on this topic were focused on Spring Boot because, starting with version 2, it uses Micrometer as its metrics framework. However, in a particular project at work we do not have access to Spring Boot let alone a recent Spring version. Therefore, I’m explaining how to include Micrometer in your non-Boot Spring application using XML configuration.

In this tutorial I will be using Spring 5 and Java 11, so not exactly the versions I’m dealing with at work, but the concepts are the same and everything can probably be copied exactly as shown here.

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A Java “DSL“ for Simple Unit Test Data Creation

I’m a person that usually writes tests before the implementation. In the context of my backup application project this has turned out to really slow me down. But it’s not just a problem of my personal projects. It also affects my professional work. 

Here’s the issue: for some tests you need test data and generating that test data can be a tedious task, depending on the complexity. This has caused me to procrastinate on my backup app. So, one evening, after having thought about this during a workout, I grabbed my laptop, sat down in my comfy bed and wrote a “DSL” that makes creating the data much simpler. Not only is it easier to create the data now, allowing me to continue at a faster pace, it’s also much more readable and the test setup doesn’t clutter the test case anymore. This is a very important aspect of a test. What good does it to have one if, after some time, you have to update it and don’t understand what it does anymore?

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Writing a Custom Backup Solution

If you are a user of any form of computer and care one bit about your sanity, then you probably have a backup strategy. Otherwise, if all hell breaks loose and your whole computer burns to ash or the hard drive melts to a heap of metal, turning it into an ugly door stop, you’ll likely be kinda angry, maybe slightly pissed, your pulse most definitely at 180, that you’ve lost all your data. I’d certainly be, especially about all my pictures of all the festivals and places I’ve been to. 

(And maybe some family 😅)

But, to be honest, I’ve been a bit lazy about backups for some time now. I do have copies of all my important files, but that’s not a backup. It’s a copy. A backup lets you go back in time and get an older version of a file or folder, not just the most recent one that has been synced.

So why is it, that I’m not as diligent as I should be? There are a few factors in that equation. It’s laziness for one, knowledge that I do have at least one copy, the fact that I haven’t had any data loss so far and stinginess. Why the latter? Up until now, being a Windows user (not any more though, on my main machine), I was relying on Acronis True Image, a commercial backup software. However, the version that I own – 2014, I think – stopped being reliable in one of the past Windows 10 versions. I simply don’t want to spend the money any more.

I’m not here to tell you that I have changed my mind on that. No. I’m, of course, coding my own solution. Why wouldn’t I? Everything is done multiple times in the Open Source community.

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Using Groovy Spock in a Maven Java Project

Groovy Spock is a testing framework that can be used as an alternative to the venerable JUnit. In Java projects it’s probably very common (I don’t have any data, just an assumption based on how I think) to also use a Java based testing framework. The most widely known is JUnit, although not the only one of its kind (e.g. see this article on DZone). However, Java’s syntax can sometimes be rather cumbersome and verbose, and this is where a dynamic language like Groovy can help. It is often used to create nice and interesting DSLs, e.g. as the basis of the Gradle project or, as in the case of Spock, for testing.

Here’s how to integrate the Groovy Spock testing framework in a Maven based Java project.

One thing up front: I’m no fan of Groovy. I’ve worked with Grails projects for several years and using Groovy has more than once proven to be a problem. Especially in very large applications. However, I do see the benefits it can provide in certain situations and I have come to like the more expressive, although sometimes odd to read, Spock DSL in tests.

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Grails Startup Error: ASSERTION FAILED at JPLISAgent.c

Grails always has something new to offer, not only features but also random bugs (unfortunately). Out of the blue I couldn’t even let Grails show its own version (grails –version) let alone perform any other action. This is all I got for each and every command I tried to execute.

*** java.lang.instrument ASSERTION FAILED ***: "!errorOutstanding" with 
message transform method call failed at 
../../../src/share/instrument/JPLISAgent.c line: 844 
Exception: java.lang.StackOverflowError thrown from the 
UncaughtExceptionHandler in thread "main"

The following runtimes were used:

  • Windows 7 64bit
  • Java 7 Update 71 64bit
  • Grails 2.4.4

Of course I removed all temporary files and folders, the “target” folder of the project and the “.grails”, “.groovy”, “.m2” and “.ivy” folders in the user directory. Nothing helped. Some say it has to do with forking processes, but playing with those settings didn’t change a thing. After all, the error happens way earlier.

Then I came across a post that mentioned to create the “.inputrc” file (on a Linux system) because through debugging it was found that Grails tries to access this files. Well, I’m not using Linux, but since I was already in the “helplessly desperate” phase I wanted to give it a shot. Surprisingly, this file already existed.

Solution: I deleted “.inputrc” from the user folder et voilà, Grails worked again.