is J2ME simple?

A few friends who want to learn J2ME have asked me this question. I think there are two answers to this question.

The J2ME is simple.

The simple, more important reason is that J2ME development uses Java, leaving the Platform Technology category (J2SE,J2ME,J2EE), the Java language itself is simple, or "concise" more powerful. Java Code makes people look more comfortable and intuitive than C + + programming code.

On the other hand, J2ME's SDK is very rich, the configuration is very simple, if the use of powerful Ides (such as JB and Eclipse, but in J2ME development, I prefer to JB), then there is a certain Java foundation, J2ME start is not difficult.

J2ME is not easy.

More people say J2ME is simple because it is "small", the so-called "small" mainly for its API less. "It's over in two or three weeks," someone said. But I cannot agree with this view. In fact, because it provides less API, it makes J2ME more challenging than traditional programming. We need a lot more "self-reliance" than J2SE and EE, which provide a rich API. The only API provides us with the most basic functionality, and the rest depends on the programmer to explore. If all of the features you need are already implemented by off-the-shelf APIs, then we no longer need to learn and research, as long as an API manual is enough.

The second difficulty with J2ME is that it is also a problem that is common to all mobile device based development. Memory limitations, processing speed constraints let us have to discard a lot of good things, for each line of code to do as much as possible optimization, optimization and optimization, in memory usage and performance to find a balance between the point. In J2ME we not only want to reduce the creation of objects, even the reference to the object to do less. In such a premise developed by the excellent should, games, software, can be said than the desktop platform for the development of a more gold content.

31st, the same is the public problem facing mobile development: Multi-model adaptation is difficult. Unlike the desktop platform, the difference between mobile devices is huge, from hardware screen resolution, memory, processor to the bottom of the KVM implementation, to support the J2ME specification is not the same, which makes the "one compile, run everywhere" commitment in almost a laughingstock. However, in any case, J2ME is still the best choice for mobile domains across platforms. Because both smartphones and traditional handsets, regardless of the system they use, they all support Java, even if the need for a variety of changes, the cost is much less. At the same time, also test the programmer's design capabilities, a well-designed program can reduce the cost of adaptation to the least.

The last question is that there are many bugs in the KVM, but Sun doesn't seem to have any responsibility. We all know that Java development is divided into two steps: norms and implementation. Sun and many manufacturers to develop specifications, and then by the various manufacturers according to their own equipment to achieve. However, do not know whether the manufacturer's design level is limited, the current many models of KVM implementation can not be satisfactory, the bug is simply a dime, such as the most classic Nokia 6600, really for it to do the development of the people should have a deep experience. This, in turn, adds to the difficulty of developers doing more than one model fit. These bugs can fully test programmers ' ability to debug: But over time, I believe this will improve, and Nokia has been rolling out the S60 model software upgrades to fix the bugs. However, for a closed operating system S40 model, you can not think of (in fact, S40 bugs are much less).

In summary, J2ME is not as "simple" as most people think, or, J2ME's introduction is simple, but if you want to do "proficient", but also need to master a variety of mobile development characteristics of the program design, debugging skills, is not an overnight work.