mjCoAP: An Open-Source Lightweight Java CoAP Library for Internet of Things Applications - Interoperability and Open-Source Solutions for the Internet of Things - page 130

CoRE WG draft-based CoAP extensions, such as blockwise transfer, resource
observing, and HTTP/CoAP mapping. The library supports the J2SE, J2EE,
J2ME/Embedded Java platforms, thus making it suited to being used on a wide
range of devices. mjCoAP is characterized by a layered architecture with the
following layers (in ascending abstraction order): Messaging, Reliable transmis-
sion, and Transaction. The proposed library is extremely lightweight and can
be used for fast development of CoAP-based applications. In order to assess the
design goals of interoperability, development simplicity, and code reusability,
we have presented a long-running CoAP-based application scenario for real-time
environmental monitoring, comprising heterogeneous devices and different CoAP
implementations. A performance evaluation of the mjCoAP library has also been
presented. The results show that mjCoAP's performance is comparable to that
of Californium in terms of average response time and maximum number of con-
current requests that can be handled. In conclusion, mjCoAP provides several
interesting and useful features that can make it suited for the development of
CoAP-based applications, by achieving the design goals of extreme simplicity
and small footprint. Moreover, due to its compatibility with J2ME/Embedded
Java platforms and its performance, the design principles and implementation
of mjCoAP make it a perfect fit for Java-enabled limited devices (such as smart-
phones), while Californium is designed for unconstrained devices to be used for
developing scalable and high-performance IoT Cloud services.
Acknowledgments. The work of Simone Cirani and Luca Veltri is funded by the
European Community's Seventh Framework Programme, area “Internetconnected
Objects”, under Grant no. 288879, CAL IP SO project - Connect All IP -based Smart
Objects! The work reflects only the authors views; the European Community is not
liable for any use that may be made of the information contained herein. The work of
Marco Picone is funded by Guglielmo srl, Reggio Emilia (RE), Italy.
References
1. European Community's 7th Framework Programme: CALIPSO - Connect All IP-
based Smart Objects. URL http://www.ict-calipso.eu/
2. IETF Constrained RESTful Environments Working Group. http://tools.ietf.org/
wg/core/
3. Shelby, Z., Hartke, K., Bormann, C.: The Constrained Application Protocol
(CoAP). RFC 7252 (Proposed Standard), June 2014
4. Fielding, R.T.: Architectural styles and the design of network-based software archi-
tectures. Ph.D. thesis, University of California, Irvine, AAI9980887 (2000)
5. Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., Berners-
Lee, T.: Hypertext Transfer Protocol. HTTP 1.1. RFC 2616 (Draft Standard),
June 1999. Obsoleted by RFCs 7230, 7231, 7232, 7233, 7234, 7235, updated by
RFCs 2817, 5785, 6266, 6585
6. MQTT: Message Queue Telemetry Transport. http://mqtt.org/
7. Vinoski, S.: Advanced message queuing protocol. IEEE Internet Comput. 10 (6),
87-89 (2006)