Java for Mobile Phones Alexandr Koloskov Lead Developer Reaxion, Corp. Copyright 2001 © Reaxion, Corp.

Topics map Java programming for mobile phones Usage of XML technologies in mobile phones.

Is mobile phone a good platform to develop for? They are wide-spread They are easy to use They are always-on But, how they interact with PDAs? And, sure, they are not so powerful…

Typical software for mobile phone. Let’s imagine… Digital wallet MP3 player Electronic map (with GPS support) Contact List (shameless plug) Instant messaging PIM Games

New generation of mobile phone They have GRPS connection Power CPU and lot of memory Color display Executing applications (even in Java)

Models Motorola i85s and i50s Siemens SL45i Motorola Accompli (with touch screen support) Nokia Communicator 9210 and 9290

Motorola i85s – the pioneer. Pros and Cons + OTA (Over The Air downloading) + Already on the market - Tiny memory - No valuable extensions like TAPI - Ugly design (personal opinion) - Silly 16-character limit on class names - Ugly uploading scheme But this is only beginning…

What’s wrong with MIDP Poor UI toolkit No TAPI support One MIDlet at time Can’t run external application, so cooperativity is out of issue. No floating point support

Future Despite of problems, future is bright… Right now, mobile phone is good as terminal client to various web-services. This is a topic of next chapter.

Usage of XML technologies in mobile phones. Phone is useful for little applications or as mobile terminal Terminal doesn’t need to be powerful

C-S Communications Call methods from server Exchange data User Interface

WAP – simple, many sites supports it, but slow, static and limited HTML- too heavy, but has widest auditory, so Links style browsers are useful Proprietary – custom format (like Mozilla’s XUL)

Remote Method Invocation HTTP is most widely enabled transport SOAP – Simple Object Access Protocol XML-RPC – Alternative variant Proprietary – maybe efficient, but hart to integrate with existing solutions.

Exchange Data SyncML – absolute winner. Recommended to mobile phone vendors by GSM Consortium. No available open-source Java implementations.

XML Parsing for J2ME kXML – most feature-rich, supports namespaces, mixed content, PCDATA, comments, written especially for J2ME, backed by Lutris, Corp. There some extensions like kDOM, kSOAP, WAP parser. nanoXML – very small (6 Kb), doesn’t support mixed content tinyXML – quite small (16+ Kb)

How to put it all together? Sample client architecture: Transport (HTTP connector) Codec (Compressor/Decompressor) SOAP stack SyncML stack Browser (supporting at least WAP) Local storage

Shameless plug Tequila project is what we doing here in Reaxion. It uses described architecture, but also contains some know-how allowing to inexperienced users to obtain all features of Internet.

Scheme of our client UI toolkit XML parser Local storage HTTP connector Data codec SOAP connector SyncML synchronizer Contact ListBrowser

Contacts. Alexandr Koloskov This presentation is available through

Thanks for patience!