We talk to many experienced Mendix developers daily, and we even are experienced Mendix developers ourselves. Many times the issues with java dependency in Mendix came up. In short, you can extend the Mendix platform with Java code. In many cases, the Java code will leverage existing Java Libraries (Jars). When you download an App Store module with custom Java (almost all modules have this), you also download the Jar files used by the module. These Jars create risks from a maintainability and security perspective. That is why we decided to tackle the problem.
With great pride, we have introduced the Java Libraries feature in ACR version 2.6!