If you have not been "lost" on some remote island for the last few years, you already now that SWT provides a powerful java based UI toolkit for desktop applications. And you are also aware that toolkits with similar capabilities exists to provide alternatives to SWT. The situation for the SWT's mobile sibling eSWT is quite different. On the mobile market, there is only one UI toolkit with the ability to reach a large number of mobile devices, that is LCDUI. (Yes I know, eSWT is the second but let's not get into that)
Although there are incentives to correct that, lack of sophisticated infrastructure API is a fundamental problem in mobile java world today and LCDUI is not an exception. LCDUI provides a very limited API. This API provides very basic widgets and plumbing for developing custom widgets. As a result most of the mobile java applications we have today are either games or applications that has developed their own widget sets basically form scratch. For some, developing own widget set may sound like a cool idea, but this is hard work and for mobile it includes extensive testing for all the mobile devices targeted.
eSWT inherits a subset of SWT widgets and adds some widgets specific to mobile world. This supplies an adequate API for most applications, for those missing pieces it is possible to provide custom widgets based on eSWT widgets. Further, It is even possible to use some of the existing custom widgets that have been developed for SWT. eSWT is trying to fill a gap present on the mobile java UI toolkits. As the availability of it grows to cover more devices and mobile platforms, we will see more of eSWT in our pockets for sure. The real curious thing is whether can eSWT can change the way we think about mobile java user interfaces.