Dong-il Cho, Journal of Internet Computing and Services, Vol. 26, No. 5, pp. 95-102, Oct. 2025
10.7472/jksii.2025.26.5.95, Full Text:  HTML
Keywords: Emergency Alerting System, messaging system, Virtual Thread, Virtual Thread Hang, multi-threading, Java Virtual Machine

Abstract

The Ministry of the Interior and Safety (MOIS) of the Republic of Korea transmits emergency disaster alerts to the public via mobile communication networks. To overcome the limitations of traditional mobile emergency messaging systems, MOIS provides this information as an open API through the Disaster and Safety Data Sharing Platform, thereby promoting the development of private-sector platforms. This study designed and implemented a Mass Emergency Alert Messaging System (MEAMS) that utilizes MOIS’s emergency disaster alert open API to deliver alert messages and user location-based supplementary information to various devices within disaster-affected areas. MEAMS must maintain simultaneous connections with numerous devices and deliver messages promptly to all target recipients. To meet these requirements, we integrated Virtual Threads, whose performance has been validated in multiple prior studies, into the network-intensive, blocking I/O-oriented architecture of MEAMS. Based on these assumptions, we conducted performance verification with the expectation that MEAMS would demonstrate high throughput and responsiveness. However, contrary to our expectations, MEAMS encountered a complete system halt at a specific point during operation. Upon investigation, we identified a critical scheduling-related flaw in the JVM's implementation of Virtual Threads. This issue can arise in systems like MEAMS requiring massive concurrent connections and high message dispatch reliability. In this study, we analyzed the causes of the problems of Virtual Thread in MEAMS and proposed alternatives.

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