Where can I learn more about Classpath, the Java class loader, JDK tools and utilities?
Veryant's documentation is a good place to start.
There is a section on isCOBOL and Java in the isCOBOL Evolve documentation, under "Introduction", "The Basics".
One of the chapters is about class loading. The 2022 version of that documentation is at:
Class loading (veryant.com)