原文：
J2ME basics
The biggest benefit of using the Java platform for wireless device development is that you're able to produce portable code that can run on multiple platforms. But even with this advantage, wireless devices offer a vast range of capabilities in terms of memory, processing power, battery life, display size, and network bandwidth. It would be impossible to port the complete functionalities of an application running on a sophisticated set-top box to a cell phone. Even for similar devices such as PDAs and advanced smart phones, establishing portability between the two often poses a strain to one device and underutilization of the other. Real portability can only be achieved among groups of similar devices. Recognizing that one size does not fit all, J2ME has been carefully designed to strike a balance between portability and usability. ………………

译文：
J2ME 基础知识
在java平台上做无线设备开发的最大的好处是你的代码能够在多个平台移植。但是即使有这样的优点，各种无线设备在内存，处理能力，电池使用寿命，显示尺寸，和网络带宽等方面都有很大的不同。所以把一个运行在成熟机顶盒上的应用程序的全部功能都移植到移动电话上是不可能的。即使是在相似的设备（如PDA和高级智能电话）之间建立可移植性也常常使一种设备超负荷而另一种设备利用不充分。真正的移植性只有在一组相似的设备之间才能实现。因为认识到一种规格不能满足所有设备，j2me在设计时就努力的在可移植性和性能方面取得一个平衡。 ………………