== Why is this an issue?

When several packages are involved in a cycle (package A > package B > package C > package A, where ">" means "depends upon"), that means those packages are highly coupled, and there is no way to reuse/extract one of those packages without importing all the other packages. Such cycle could quickly increase the effort required to maintain an application and embrace business change. 

SonarQube not only detect cycles between packages, but also calculates the minimum effort to break those cycles. This rule logs a violation on each source file having an outgoing dependency to be cut in order to break a cycle.

