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Setup IntelliJ for development of DSP-API

TODO add "Setup VS Code for development of DSP-API"

Create an IntelliJ Project for DSP-API


Setup IntelliJ Code Formatter

Use Scalafmt in IntelliJ IDEA to format Scala code.

In IntelliJ editor setting (Preferences -> Editor -> Code Style -> Scala), choose Scalafmt as formatter and check the box for Reformat on file save as shown below:

screenshot 'setting tab size'

Use IntelliJ IDEA's Run/Debugger Configuration with Knora


Profile Knora Using VisualVM in IntelliJ

First, download and install VisualVM.

Then, in IntelliJ, under Preferences -> Plugins, search for the VisualVM Launcher, click on "Search in repositories", install the plugin, and restart IntelliJ. IntelliJ's toolbar should now contain a button with a green triangle on an orange circle, with the tooltip "Run with VisualVM":

screenshot 'Run with VisualVM button'

You can use this button to run the class and profile it in VisualVM. The first time you do this, IntelliJ will ask you for the path to the VisualVM executable. On macOS this is /Applications/

When VisualVM starts, it will open a window like this:

screenshot 'VisualVM overview'

To use the profiler, click on the "Sampler" tab, then on the "CPU" button:

screenshot 'VisualVM sampler'

Now run some DSP-API operations that you're interested in profiling, preferably several times to allow the sampler to collect enough data. Then click on the "Snapshot" button:

screenshot 'VisualVM snapshot

In the snapshot, you'll see a list of threads that were profiled:

screenshot 'VisualVM snapshot'

You can then browse the call tree for each thread, looking for Knora method calls, to see the total time spent in each method:

screenshot 'VisualVM call tree'

Last update: 2022-04-05