1. Building a Reliable Remote Communication Device with Java ME
JavaOne San Francisco CON8004 
Leonardo Lima – V2COM
Tiago Padovani – V2COM

2. Introduction

3. About the presenter (Leonardo)
Software Development Manager at V2COM, leading the development of both embedded software for edge/field devices and server-side software that receives field data and enables fast communication with remote devices.
Eight years of development and architectural experience on mobile, embedded and server platforms to enable management and operation of highly scalable and fast telemetry and network control systems.

4. About the presenter (Tiago)
Lead Software Developer for Embedded at V2COM, leading the development of embedded software for edge/field devices.
Six years of development and architectural experience on embedded Java platforms, building reliable communication devices that stays on the field for years.

5. About the presentation
Explore how to build reliable remote communication devices that must stay online, connected, and transmitting field data without interruptions. Using Java ME, a solid foundation was built that can be used to deploy many kinds of applications in the field, with fast, reliable development. In this session, see what the difficulties, ideas, and insights were that led to this foundation, which is currently in use in more than 50,000 devices in Brazil and Latin America to connect more than 800,000 field devices.

6. V2COM is a leading Latin American provider of Smart Grid technologies and Advanced Metering Infrastructure (AMI). Our offer includes hardware, software and services that can reduce losses and increase water and energy efficiency, currently connecting more than devices.
Besides the economic gains for our customers, we develop technologies with significant impact on the environment (avoiding losses of important natural resources) and with social responsibility (our Smart Grid systems can be used to offer free internet access in challenging areas)

7. Awarded 2013 Java Business Innovation Award
JCP member, nominated for EC election
More interaction with community to foster Java ME development in this age of IoT!

8. V2COM clients
Meter Reading
Network Control

9. The scenario

10. Intelligenceware Suite
Legacy Systems
Intelligenceware Suite
WAN
Terminal
LAN
Devices
IP Network
Wireless Network
Local Network

11. Use cases Automated Meter Reading (AMR) Network control
Read “dumb meters” and send data over to Utility
Both energy and water meters
Can be any meter, really!
Like our Zigbier refrigerator’s temperature sensor, with alarms for too cold or hot!
Network control
Remotely connect SCADA systems to field devices like reclosures
“transparent pipe” between SCADA and Device
DNP3/IEC104 protocols and proprietary as well

12. Use cases 1 3 6 4 2 5b 5a

13. The techonology used Gateway:
Oracle Java Micro Edition 1 (Java profile IMP-NG version 2 & CLDC 1.1 Hl), embedded in a Gemalto TC65i module.
Started with Siemens TC45, 6 years ago!
Intelligenceware Suite:
Oracle Java Enterprise Edition 5
Oracle Java Standard Edition 6
Oracle Utilities Meter Data Management 2.0

14. Living an embedded life

15. The 3 commandments
“If the device has a power from source, it must be on”
Our first commandment is to keep the device always on.
If it can be on, it must be on, no matter what.
“The firmware must be remotely upgradable”
One of few certainties in software developments is that bugs always happen!
So, we must be able to OTAP (over-the-air provision) the device
“If it’s on, it must be online and connected (or trying to be...)”
It doesn’t suffice to be on. It must be also be avaiable so that communication can happen

16. Hardware choices WatchDog Dual Sim Card Dual Serial Java ME
One of the few always-must-have circuit for any device is a watchdog to turn it on in case it turns off or there’s a lock-up
Dual Sim Card
GPRS infrastructure is not very reliable, so it should be able to have option in case of carrier failure
Dual Serial
Many field devices have two serial ports, so being able to connect to both at the same time is very important
Java ME
Being able to run Java ME allows many advantages over C

17. Software choices - Separation of concerns
“Hardcore”
Abstracts board specifics details (like GPIO)
“Zion”
Handles common infrastructure (backend connection, message queues, locks and so on)
Abstracts Modem commands, so there’s one for each avaiable module (Cinterion/Gemalto; Motorola; Telit)
“App”
Holds application logic - As tailored as clients need it to be
Ranges from a simple Transparent (TN) to Automated Meter Reading (AMR)

18. Hardcore Handles board specifics Modem/AT Connection SMS/GPRS logic
GPIO
Watchdog

19. Zion Defines command shell Handle TCP communications
Kitchen sink utils (math, string, locks, queue)
Event Bus
Extendable to handle “fatter” functionalities
CSD
SNMP monitoring

20. Application Handles only business logic and protocol
Fast changes to acommodate business logic
After the first few cicles, it stabilizes

21. Package Diagram mobi.v2com.zion... Application Control Hardcore
Communication
Event
Protocol
Tools
Utilities
... and application specifics as well

22. Challenges
Problems faced, solutions provided!

23. How to keep the device on?
Problem:
Module can throw Exceptions (EXIT CODEs) that shuts down the application
Solution:
Hardware Watchdog!
Dedicated QG8 to handle only this (power on/off)
10 minutes timeout: either the firmware “swings” the GPIO, or it gets powered off then on
Many other software watchdogs...
Many other conditions can mean a “lock up”

24. How to keep the device online?
Problem:
GPRS connections can be unstable, specially when needed most: thunderstorms and harsh weather condition
Solution:
Dual-SIM cards, so if a network fails, there can be another
Many soft watchdogs to retry attachments
Turn on/off modem, like our phones
Attach/Deattach

25. How to get behind public APN firewall?
Problem:
Can’t use a server socket while communicating on public networks!
Solutions:
Device polls server, asking for new commands
This doesn’t work for always-on connection needs
Expensive on resources
Software Switch (server side)!
Meet-in-the-middle approach

26. How to keep the TCP connection up?
Problem:
You don’t know the connection is broken until you have a blocking read() or write()
TCP keep-alive is not enough
No module support for this...
Solution:
Keep-Alive packets
Application-level bytes sent to make sure connection is not off

27. How to keep the firmware updated?
Problem:
There are MANY devices deployed, each with a software version
No one wants to mass-deploy...
Not all updates are required for all devices
Solution:
Axon has control of each version
Updates are dispatched as needed and/or cleared by client

28. How to debug in-device? Problem: Solution:
No simple logging framework to write log to
Log redirection works for serial port only, not remote connections
Solution:
Built a simple logging framework that handles debug level, message, threads

29. How to debug off-device?
Problem:
How can we run/test outside the framework?
Many classes you depend on are hardware specific (Files, Connections)
Solution:
Built a simple “java abstraction layer” that implements javax.microedition classes (and proprietary ones too) that runs on Java SE on the desktop.

30. How to keep historical, debugging info?
Problem:
No long-term storage on devices to keep logs
Flash memory can hold at most 30 minutes of logs
The logs you need are the ones when device is unreachable, but alas, you can’t download it.
Solution:
Have a “black box” flight recorder
Small, coded files that can hold critical information for weeks

31. How to synchronize access to resources?
Problem:
Access to system resources must be synchronized
Serial device, system files
synchronized can lead to unknown lock ups
Some race conditions hard to track ando also some bugs...
Solution:
Custom implementation of Java SE’s Lock
ReentrantLock inspired
Added few methods for convenience
tryLock, so that you lock if you can, but don’t fail if you can’t
fastLock, for locks that should last than 2 secods

32. How to default parameters?
Problem:
Same firmware for different clients with different needs, lots of parameters
Parameters for APN, Serial, Timings and such
Flash memory can get corrupt and you lose your parameter files!
Solution:
Use JAD parameters
JAD can be custom tailored to each client
Can provide good defaults

33. Pending challenges...
... because you can’t win them all...

34. Many pain points are still there
Make smaller binary fragments?
And small updates over the air.
Run multiple applications at the same time?
More “permanent” and/or remote logging
Security issues
Better management of keys
Anti-tampering measures

35. Incoming changes
Java ME (r)evolution

36. Java ME 8 has much new features!
Java ME 8 seems to have addressed some, if not most, this problems and abstractions
Device I/O
Access Point
NIO
... And many others!
Some still need works
No concurrency support might mean no locks...
We’ll work with JSRs to try and address the rest of them
V2COM is joining the JCP EC to help foster Java ME evolution

37. Q?

38. Thanks!