kemitix-checkstyle-ruleset/builder/src/main/resources/rules/ThrowsCount.md

Restricts non-private methods to only throws 4 distinct Exception types. Exceptions should be hierarchical to allow catching suitable root Exceptions.

See [Effective Java], 2nd Edition, Chapter 9: Exceptions

Valid:

void doSomething() throws IllegalStateException, DowsingServiceException,
    BalancedBudgetException, ManagementInterferanceException {}

Invalid:

void doSomething() throws IllegalStateException,
    DowsingNotPermittedException, DowsingServiceNotReadyException,
    BalancedBudgetException, ManagementInterferanceException {}