Sun Mobile Device Technology - Archived Technical Tips

Summary of CLDC-Based Profiles
Explores CLDC and the Profiles defined for use with the Connected Limited Device Configuration. Enrique Ortiz writes about the most common Java ME execution environment. (June 2006)

An Overview of the File Connection Optional Package
Describes how the basic scaffolding for file I/O is supported. (September 2003)

An Overview of the PIM Optional Package
Describes the J2ME interfaces for personal information management data. (September 2003)

The CDC and Foundation Profile 1.0 release
Learn how Connected Device Configuration and Foundation Profile work together on larger wireless devices. (May 2001)

Information Module Profile
The Information Module Profile (IMP) is a subset of MIDP 1.0 specification. The IMP specification removes MIDP's display and input mechanisms. The profile is suitable for deployment on devices with either no user-interface or a non-conventional user interface, for example: vending machines or tracking devices. Read more about IMP and it's future. (August 2004)

SOA Without SOAP: The Java ME Perspective
In Part 3 of his SOA series Eric Giguere explores how to do SOA when the target device does not support Web Services (JSR 172). Dig in to learn what your options are. (June 2007)

Ajax-like Asynchonous SOA Calls with Java ME
Part 2 of Eric Giguere's Web Services series details the mechanics of how to do SOA on the Java ME platform. Jump in and master the Ajax idiom. (April 2007)

Externalizing Resources - Persisting Images in RMS
MIDlet suites becoming too large to OTA? Does your suite contain images you would like to vary over time? Follow along with Enrique Ortiz as he describes a technique for stashing images in an RMS. All goodness. (October 2006)

Service-Oriented Architecture and Java ME
Take ubiquitous connectivity, a common transport - HTTP, a data representation standard - XML and Java ME, roll it all together and we have Web Services. Always with us and always on. Read Eric Giguere's introduction, then stay-tuned for more in the SOA series. (October 2006)

Obfuscating Your MIDlet Suite
with a few simple steps you can reduce the size of MIDlet suites using an obfuscator. Reduced size equals smaller, faster downloads - saving OTA time and money. Read how to integrate obfuscation with the Sun Java Wireless Toolkit or your Ant build scripts. (October 2006)

Accessing a Resource over HTTP
Concise example of how to use the HTTP GET method to retrieve content given a URI and MIME-type. Read this one carefully, it will be used in a future technical tip. (September 2006)

A Generic Connection Framework cheat sheet
The Generic Connection Framework (GCF) is based in CLDC but can be found in many profiles and optional packages. Presented here, a summary of the many schemes based on the GCF with interface hierarchy, BNF and examples. (April 2005)

MIDP Application Properties
Increase the flexibility of your MIDlets by saving configuration settings as application properties. Save development and test time by keeping settings in one convenient location. (April 2005)

MIDP Provisioning With Servlets
This tech tip shows you how to write a simple servlet that automatically selects the right version of your application and delivers it through the magic of over-the-air (OTA) provisioning. (April 2005)

Handling Varied Content in J2ME Applications
The Content Handling API (JSR 211) (CHAPI) provides a mechanism for a MIDlet to handle incoming content based on MIME type, URL or content handler ID. Read about the CHAPI framework and it's many uses. (March 2005)

Sharing Data Between MIDlet Suites
A discussion of MIDlet data sharing using the MIDP 2.0 RMS package. How to share data, access control and security topics are presented in the context of a working example. Source code is available, ready to use with the J2ME Wireless Toolkit. (March 2005)

Game Canvas Basics
Introduces the MIDP 2.0 GameCanvas class and the game loop concept. Required reading for all aspiring "first person shooter" developers. (December 2004)

Understanding MIDP System Threads
Describes the multi-threaded aspects of the J2ME application environment. Understanding the interactions between systems threads, user-interface and application threads will help in avoiding MIDlet deadlock. (December 2004)

Getting Started With Bluetooth
JSR-82 brings Bluetooth API's to the J2ME environment. Read the tech tip and begin experimenting with Bluetooth today using the Wireless Toolkit 2.2 Beta. (October 2004)

Writing a Custom Counter Component
MIDP 2.0 introduced the javax.microedition.lcdui.CustomItem class. As the name implies, a developer can now create custom UI components by extending the CustomItem class. This tech tip designs and implements a UI component for displaying a numeric counter and of course, source code is available. (October 2004)

Alerts in MIDP 2.0
Don't leave the user guessing, provide visual feedback of MIDlet progress using MIDP 2.0 alerts. New alert features provide an interface to associate a javax.microedition.lcdui.Gauge item with a javax.microedition.lcdui.Alert. By adding a javax.microedition.lcdui.CommandListener interface alerts can also provide users more control over MIDlet processing. Sample source code is available for download. (August 2004)

A Custom List Component for MIDP 2.0
The MIDP 2.0 specification allows the creation of custom user-interface (UI) components. This tech tip illustrates custom UI component development by way of an example "virtual list" component. The source is available for download. (July 2004)

Custom Item Traversal in MIDP 2.0
Navigating between and within UI components is a common user activity. Learn about the MIDP 2.0 javax.microedition.lcdui.CustomItem traversal model to enhance your custom UI components. (July 2004)

Interaction Modes in MIDP 2.0
MIDP 2.0 introduces three user interaction modes in the javax.micoredition.lcdui package. Custom UI items can discover the interaction modes available in an implementation at run-time. Learn how to identify and dynamically adapt to interaction modes in your javax.microedition.lcdui.CustomItem components. (June 2004)

HTTP POST Basics
A presentation of the benefits and usage model of the HTTP POST method. The POST method is explained and compared to the HTTP GET method. Code samples illustrate the usage of each method in the MIDP environment. (June 2004)

Invoking Platform Services in MIDP 2.0
Learn how to use the MIDP 2.0 javax.microedition.midlet.MIDlet.platformRequest method to access features outside of the J2ME run-time environment. The J2ME Wireless Toolkit supports the platformRequest method and can be configured to invoke a user-specified service. (May 2004)

Retrieving MIDlet Attributes
This tech tip describes how to use attributes with a MIDlet suite to add flexibility and reduce test time by separating configuration data from the Java source code. The tech tip also discusses using attributes in both trusted and untrusted MIDlet suites. (May 2004)

Personalizing Wireless Java Applications
Learn how to store user-specific data on a J2ME device to enhance the user experience. Personalization stores the most commonly entered user data on the device. This data does not have to be re-entered by the user and can be shared by co-operating MIDlets. (April 2004)

Converting Flash Movies to MIDlets
This tech tip describes one approach for providing more rich client content on J2ME devices. One company provides a tool that will convert Flash movies to a form suitable for use in a MIDlet. (April 2004)

Text Wrapping in MIDP
The Mobile Information Device Profile (MIDP) 2.0 provides several enhancements for text wrapping. This tech tip provides some hints and guidelines on text wrapping in MIDP. (March 2004)

Preventing Screen Lockups of Blocking Operations
This tech tip shows how to prevent screen lockups when making connections to the network. (March 2004)

Scraping HTML Pages for Content with the Mobile Information Device Profile
On occasion, you may wish to extract information from a page of HTML on a web site, in a procedure commonly called page scraping. The code presented here parses an HTML page inside a servlet or directly from a Mobile Information Device Profile (MIDP) application. (March 2003)

Over-the-Air Provisioning with the J2ME Wireless Toolkit
This tech tip shows how to use "Run via OTA" feature in the J2ME Wireless Toolkit version 2.0 to test the deployment of MIDlets in an Over-the-Air Provisioning environment. (March 2003)

The J2ME Wireless Toolkit WMA Console
This tech tip describes version 2.0 of the J2ME Wireless Toolkit which offers many new features and improvements to wireless developers. (March 2003)

The Dynamic List/Detail View Design Pattern
This tech tip shows how to use the Dynamic List/Detail View design pattern, sometimes referred to as the Master/Detail View design pattern, to display the same information across multiple screens, with a simple and predictable user interface. (March 2003)

Using Custom Items in MIDP 2.0
This tech tip shows how to use the MIDP 2.0 CustomItem widget to develop new custom form elements. (February 2003)

Getting Started with Inter-Xlet Communication (IXC)
The Personal Basis Profile (PBP) - and by extension, the Personal Profile (PP) - defines a new application model called the Xlet model. One appealing feature is that Xlets running on the same device can communicate with each other using inter-Xlet communication, IXC for short. (February 2003)