If you need to include a JAR file in your library, put it in the lib directory and add a reference to the classpath (in CloverDX Designer, go to: Project properties → Java Build Path → Libraries, click ok Add JARs… and select JAR file from your ${PROJECT}/lib directory. This applies especially to libraries and connectors that users cannot inspect. However, do not bundle JAR files that are already on the classpath, such as Bouncy Castle or certain database/JDBC drivers to avoid conflicts.

If you need your own custom Java code to be used in the CloverDX library, put it into a proper package. The naming pattern should look like this: com.<your company name>.libraries.<libraryName>.<className>. The source code of the Java class should be stored in ${PROJECT}/trans directory. Java classes from this directory are compiled automatically using CloverDX Designer during development (for every Java class in each .java file, a .class file will be created).

Make sure you include all the .class files (compiled Java classes) in your (when exporting the library in Designer). Otherwise, the library will not be able to use the Java classes. If you use a versioning system, you may want to store the compiled classes in the repository (for example, if you use Git, do not exclude .class files in your .gitignore).