Using your SSL certificate for your Spark web application

I’ve fallen in love with Spark recently. Being unexperienced with web development, I stumbled upon Spark when I was looking for a small framework for setting up a simple web application based on Java. My learning curve has been steep and my first website (consisting of nothing but a simple form) is running smoothly.

One issue I had to deal with was using my domain’s SSL certificate (proudly sponsored by Let’s Encrypt) for the integrated web server that comes with Spark. As you can read here, a keystore and a password need to be specified in order to achieve this.

Alright, nothing easier than coming up with a password, but how do I set up a Java keystore (.JKS) that uses my certificate? A quick Startpage search directed me to Maximilian Böhm’s tutorial on JKS and Let’s Encrypt certificates.
I could skip step 1 as I had created and installed my certificates already. For step 2, I needed to locate the directory in which my Plesk installation stored the fullchain.pem and privkey.pem files. I found them in:

I copied them to a temp directory to make things easier, and then ran the following command:

After typing in and remembering the password, the resulting pkcs.p12 file could be used to create the JKS file as described in step 3:

Here, SRC_STORE_PASS is the password chosen in step 2. Make sure to remember and distinguish those three passwords! Or use the same phrase for all of them.

The result was saved as keystore.pks. I changed my Spark code accordingly:

and put the file next my JAR. Done.

Update 2017-09-02: Here’s a script that updates the keystore entry (e.g in case the existing SSL certificate has been invalided and a new one has been created).


About the author


Software developer with experience in Java, JavaFX, EMF, OSGi, and a little bit of Swift. I live and work in Munich.

I use this website mainly as a journal and personal knowledge data base.

My PGP key is here. There are other keys listed for me, but I use this one exclusively.

Fingerprint: 232F 05C4 01BE F43D 0434 0A8A 4ED3 5720 477E EF40

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