Impact of virtual threads and garbage collection on energy efficiency of Java applications for battery powered IoT devices

IoT devices are increasingly battery-powered, making energy efficiency a primary design concern. This work investigates how Java’s concurrency model (traditional OS threads vs. Virtual Threads) and garbage collection strategies affect battery lifetime. Using a smartwatch case study, we demonstrate that a modern, asynchronous design using Virtual Threads and ZGC achieves a 42% improvement in battery lifetime (7.0 h → 10.0 h) compared to a traditional blocking implementation. This improvement is driven by a 55% reduction in CPU active time and a 7 × increase in deep-sleep residency. This paper provides quantitative evidence and practical guidelines for building energy-efficient Java applications on constrained embedded devices. Sivakumar, V., Reddy, A. H. & Varma, A. N. GRU in anomaly detection for IoT: A comparative study. In Proceedings of the IEEE International Students’ Conference on Electrical, Electronics and Computer Science (SCEECS) 1–7 (IEEE, 2025). https://doi.org... [8669 chars]