Java: Java Modules (JPMS)

It can lead to tightly coupled and hard-to-maintain code.

When module boundaries are not enforced, code from one module can access internal classes from another, leading to dependencies that are hard to track and manage. In an e-commerce application, if the 'orders' module directly accesses the 'database' module's internals, any change in the database module could break the orders module, making maintenance cumbersome.