Nimrod questions

• Install4j - is there any finalization stage option in case of a failure?
• Cannot update JAR properties file with Install4j
• How to propely design a combination of many sub-classes?
• Semaphore - why my threads are running one after the other and not in concurrent?
• Why one should try throw unchecked exception over checked exception? [duplicate]
• How to properly return Optional<> of a method?

Nimrod answers