JEB 2.x requires a Java JRE version 8 as well as additional JAR support libraries to run.
If your computer is connected to the Internet, JEB will download those required dependencies automatically at start-up.
You may also choose to download dependencies manually. Select an appropriate package for your system, and drop it within the bin/ folder of your JEB installation directory.
JEB 3.x simply requires Java 8. There is no additional dependency.