Jam requires the Java Development Kit (JDK) version 11 or later. See Oracle or, better yet, install OpenJDK. On Ubuntu 18.04 and later, it is possible to simply execute:
> sudo apt install openjdk-11-jdk
In all likelihood, Jam will run on later versions (12 and 13, as of this writing) of Java SE. This has not been tested in any way, though.
While it is possible to run Jam with just a Java Runtime Environment (JRE), normal usage of Jam means authoring sort routines in Java, and compiling them against Jam as a library (further details in the Jam User Guide).
See the User Guide in the Help menu once the application is launched.
IMPORTANT: For the command below to work, make sure that the path to Java 11+ is in your system path.
The easiest way to launch Jam is to download the latest Jam-X.y.z-jar-with-dependencies.jar
from the project releases and launch it as
follows:
> java -jar Jam-X.y.z-jar-with-dependencies.jar
IMPORTANT: Make sure you have set the JAVA_HOME environment variable.
This assumes you've pulled the Git repository or downloaded the source tarball from GitHub.
> mvn package
> mvn exec:java
After making a code change, sometimes it can be useful to execute the clean lifecycle before the package phase:
> mvn clean package