I do not know what you mean about feature technology, however
I'll explain each one, and you choose:
Embedded systems: they are small machines, with limited capabilites in terms of memory, processing power, harddisk(if any)
Can be very challenging task to program on these devices
Mainly programmed in C++, or Java Micro Edition (J2ME)
SAP: It is an ERP program, used for controlling a fairly big company, with all the necessary functions for the different departments. (eg. finance, HR) etc. It is market leader, widely adopted, and quite easy to get a job , as a good SAP consultant, but it is a complex system , quite possible you will be able to learn only a few modules, programmed in a language called ABAP
.Net: Microsoft's technology for being able to program over a common platform , and common libraries, in different kind of languages, you can use a number of languages, most important being C#
J2EE: Java Enterprise Edition: it is common standard set of libraries used on a number of application servers. It is purely Java based.
Hope it helps