Lecture-Less Java-Threads Training in an Hour?

Introducing concurrent execution, forking, joining, synchronization, and load balancing of Java threads to trainees allows them to (a) create arbitrary concurrent algorithms, and (b) be exposed to the underpinnings of concurrency concepts. However, it requires the sacrifice of some existing concepts in the course in which such training is added. To keep this sacrifice low, we ambitiously explored if such concepts can be effectively introduced and tested in a single class period, which is approximately an hour, without a live lecture. Students were asked to learn the concurrency concepts by reading, running, fixing, and testing an existing concurrent program, and taking a quiz. They had varying knowledge of concurrency and Java threads but had not implemented concurrent Java programs. Both in-person and remote help were offered. They were allowed to finish their work after class, within a week. The vast majority of them who started on time finished the coding correctly and gave satisfactory quiz answers in ninety minutes. This experience suggests that such hands-on training can be usefully added to courses for training students and instructors that provide no other training in concurrency or training in declarative concepts. Our key ideas can be applied to languages other than Java.