Install a JDK

In the day-plan workshop you will need to have a Java Development Kit (JDK) installed.

There are a number of places you can get this from. [Microsoft's instructions for installing OpenJDK](https://learn.microsoft.com/en-us/java/openjdk/install) may be a useful starting point.

Your goal is that from a terminal running `java` and `javac` should show output indicating these binaries are installed and are in your `$PATH`.

Also, install the Java VSCode extension.