Migrate build configuration to Java 8
Use lambda expressions in LogPrinter.
Use interface default method for queue vacancy check. By default, queues
have unlimited capacity.
Entities with no handlers should just default implementation in abstract
Entity now.
Entities with no handlers should just default implementation in abstract
Entity now.
Remove unused states in Sample/SampleHolder
Remove unused states in Sample/SampleHolder
Merge branch 'java8'