Sun Microsystems 2 manual Introduction

C H A P T E R 1

Introduction

Customers use mobile phones and other handheld devices for many tasks, such as making phone calls, taking photographs, playing games, organizing contact information, keeping a calendar of events, and accessing web sites. It is natural for them to want to do more than one of these tasks at a time. For example, a customer might not want to shut the address book to receive a flight-delay alert. The Java Wireless Client software, which can concurrently run multiple MIDlets, meets this need.

Device manufacturers and service providers also benefit from being able to run multiple MIDlets concurrently. This functionality enables them to write built-in (resident) applications, such as address books, in the Java programming language. Applications written in the Java programming language (Java applications) are easier to write and maintain, more portable, and easier to customize than those written in native code. The Java Wireless Client software meets this need too.

In addition, the Java Wireless Client software enables MIDlet writers to take advantage of multitasking without changing their code. MIDlet suites that run in the Java Wireless Client software’s multitasking environment are no different from any other MIDlets: They have no new APIs and they have the same life cycle. The MIDP

2.1Specification advises all MIDlet writers about managing resources when the MIDlet is paused and resumed. In a multitasking environment, a MIDlet might compete with other MIDlets for resources, so it is more important than ever for MIDlet writers to follow that advice and to use resources carefully.

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