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Java on mobile phones Danish Kanojia

Mobile Java

Danish Kanojia

Introduction

Wireless communications is a broad field, covering everything from broadcasting and television broadcasting through pagers, mobile phones and satellite communications. The field of mobile phones is expanding very fast, while standards and protocols are being taken, used, updated, and sometimes discarded.

Platform and operating system used by a mobile phone are:

• Symbian is an operating system for mobile phones. Later versions of Symbian J2ME to support. In fact, Symbian is the company name, originally a joint venture by Ericsson, Nokia and Psion to develop a standard operating system the multimedia mobile phone industry. Symbian is currently owned by Ericsson (15.6%), Nokia (47.9%), Panasonic (10.5%), Samsung (4.5%), Siemens AG (8.4%) and Sony Ericsson (13.1%).

• Windows Mobile is a mobile solution from Microsoft. This platform is aimed at relatively high-end devices and Windows developers with experience. ex Imate

• BREW is a C + + based framework that has the support of Verizon. The developers of this platform you can trust the phone company for billing and implementation. However, the certification process required for such support is an obstacle for small businesses. IBM has built a JVM for BREW.

• WAP is an excellent platform cell phone. Some form of it is compatible with most modern phones, which is a strong selling point. The profit margin is at the top of WAP 2.0 XHTML. Because of this, there is little or caching of data validation can be done the client.

• J2ME is a Java-based platform for mobile phones. Includes everything needed to solve traffic problem of congestion in all departments: a graphical user interface, persistent data storage and network access. It is supported by most companies cell phone in the U.S., has no licensing issues, and is well documented.

Platform Overview Java 2

Java 2 Platform consists of three elements:

1. The Java programming language is syntactically similar to C + +, But is fundamentally different. While C + + uses pointers risk conditions and programmers have the responsibility to allocate and free memory, the programming language Java uses type-safe object references, and recovers unused memory automatically. In addition, the Java programming language avoids multiple inheritance (a likely source of confusion and ambiguity in C + +) for a cleaner build, interfaces.
2. It is a virtual machine the foundation of the Java platform. This architecture offers several attractive features: The virtual machine can be implemented to run first a variety of systems hardware and operating with Java applications binary compatible operating consistently across many implementations. In addition, the virtual machine provides tight control of executed binaries, enabling safe execution of untrusted code.
3. Finally, a wide range of applications standard programming interfaces (API) complete the Java platform. These support almost everything you might want your applications to do, from the user interface through cryptography, CORBA connectivity through internationalization.

Overall, the Java language and Java Virtual machine1 Java API make up the Java platform. On the other hand, Java platform is designed to cover a wide range of computer equipment, everything from smart cards across enterprise servers. Therefore, the Java platform comes in three flavors:

Java 2, Standard Edition (J2SE) is designed for desktop computers. Most of the time that runs on top of OS X, Linux, Solaris or Microsoft Windows.

Java 2 Enterprise Edition (J2EE) is a global platform for multiple users, applications across the enterprise. It is based on J2SE and adds APIs for server operations.

Java 2 Micro Edition (J2ME) is a set of technologies and specifications developed for small devices like pagers, mobile phones and set top boxes. J2ME uses subsets of J2SE components, such as smaller API and agile virtual machines.

Overview of J2ME

Unlike J2SE, J2ME is not a piece of software, nor a single specification. This difference can be confusing, even for developers who are already familiar with J2SE. Instead, J2ME is a platform, a collection of technologies and specifications that are designed for different parts of the small device market. Because it encompasses such a variety of J2ME devices, it would sense to try to create a one-size-fits-all solution.

J2ME, therefore, is divided into configurations, profiles and optional packages.

J2ME has two main branches.The first is based on the Connected, Limited Device Configuration (CLDC). This configuration is for small wireless devices with intermittent network connections, like pagers, mobile phones and personal digital assistants (PDA). The other main branch of the tree Is based on the J2ME Connected Device Configuration (CDC). This configuration is for larger devices (in terms of memory and processing power) with robust network connections. Set-top boxes and Internet appliances are good examples of CDC devices.

Why Java on mobile phones?

If your phone already supports WML or other markup language (such as HDML or compact HTML), is there any advantage of being able to run Java programs on it too? What can make a program in Java that a set of WML decks can not?

The first advantage is that Java is a programming language, in the proceedings / Object-oriented sense, and is used in a wide variety of platforms. WML is a declarative language, which some logic grafting procedure using WMLScript, and only used in mobile phones. Java is more suitable for complex programming tasks.

The second advantage is that Java allows you to work without connection. With a mobile phone that supports Java, you can download and install an application that can run without incurring the costs of connection, something not really can you do when you are browsing websites microbrowser the phone. You can run applications even when you're out of range, something which may be independent Europeans, but something that Americans – through our vast geographical areas and competition, incompatible networks – have to deal with on a regular basis.

Of course, you can work offline using a title with WML decks in cache, but only if the covers are designed to be cached. And I really do not have much control over what is cached, and all under the control of the browser and the creator of the roof.

The Building a Java application

There are two files necessary for a J2ME application. One is the jar file, the zip file typical classes and resources. The other is the jad, jad file contains information about the midlet (A MIDlet is a Java program for embedded devices, more specifically Java ME machine virtual) that is used by the phone at the facility.

Popular mobile java applications

Opera Mini: the revolutionary browser for nearly any mobile phone.

Personal MemoryUp Mobile RAM is a useful tool for monitoring and enhance specially designed for smartphone users

The Picasa photo browser lets Moblica view multiple public and private Picasa Web Albums and search for photos from your mobile device with Internet connection

Gmail for Mobile 2.0 is designed to be more reliable in low signal areas and provides online support base phones like the Nokia N95, Sony Ericsson W910i, and BlackBerry Curve

About the Author

Danish Kanojia a student of BCA from PCTE ludhiana.

Danish Kanojia has keen intrest in Programming

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