March 2002
Intermediate to advanced
480 pages
18h 40m
English
Content preview from J2ME in a NutshellBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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J2ME and Other Java Platforms
J2ME is intended to be the way ahead for Java on small devices, but, as noted at the beginning of this chapter, there are other Java platforms already in existence (and in use) that have similar scope. The following sections briefly summarize these alternative platforms and compare them to J2ME.
JavaCard
JavaCard is a platform aimed at smart card technology. Smart cards are the smallest environment for which a Java platform exists. The constraints of these devices are such that the JavaCard virtual machine and the small set of Java class libraries that it supports require only around 16 KB of non-volatile memory and 512 bytes of volatile memory. The scope of J2ME does not extend to platforms with this little resource, so there is no J2ME configuration that is suitable for the current generation of smart cards. You can find more information about JavaCard at http://java.sun.com/products/javacard/.
EmbeddedJava
EmbeddedJava is a JDK 1.1-based platform that is used to create software for embedded devices. These devices typically have a 32-bit processor with 512 KB of ROM and 512 KB of RAM available for the VM, class libraries, and embedded application. Since embedded devices generally serve only one purpose, it is unnecessary to include parts of the Java platform that the application does not require. In fact, EmbeddedJava allows the implementor to remove any package or class -- or even a method within a class -- that is not required, in order to fit the ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.