No. CLDC specifies the core libraries and virtual machine features for J2ME implementations on resource-constrained devices. A CLDC implementation includes a virtual machine. For instance, KVM is included in the CLDC reference implementation.

Yes. CLDC-based applications can execute in other Java Virtual Machines, provided that the required CLDC libraries, profiles, and/or optional packages are also available.

K virtual machine (KVM) is a Java virtual machine that provides the basis for the CLDC reference implementation (RI). K stands for "Kilobyte" virtual machine, referring to the small footprint of the platform. The K virtual machine is very small -- starting from approximately 70K in size.

No. A virtual machine requires a set of core libraries to run applications. Some of these libraries are packaged as a part of a CLDC implementation along with the virtual machine. In addition, the capabilities of CLDC can be extended by adding profiles such as the Mobile Information Device Profile (MIDP) and/or optional packages.

quot;Virtual machine" is the term applied to the server environments running on a piece of hardware. So, in the example above, the decoupled Linux and Windows servers running on a single blade server would be referred to as virtual machines.

In order to ship products based on CLDC, the CLDC implementation must pass the Technology Compability Kit (TCK) provided by Sun. For more information about TCK commercial licensing terms, please contact your local Sun sales representative.

The J2ME CLDC reference implementation (RI) is available on Sun's website at http://java.sun.com/products/cldc. The CLDC RI is a source code product that is provided for porting to various platforms.

The CLDC HotSpot[tm] Implementation is a high performance, battery-preserving virtual machine that is compliant with the CLDC specification. It not only offers significantly improved performance over the KVM, but it also offers greater portability and faster time to market. The CLDC HotSpot Implementation is suitable for devices based on ARM microprocessors/controllers, and with 512KB to 1MB of total memory available for the Java technology stack.

There are a number of tools and emulators that are available on the market depending on the developer's needs. Developers can utilize the CLDC reference implementation for basic CLDC development. Many developers also utilize the J2ME Wireless Toolkit to develop applications based on CLDC, MIDP, and other optional packages.

Jikes RVM (Research Virtual Machine) is designed to execute Java??? programs that are typically used in research on fundamental virtual machine design issues. It provides the research communities with a flexible testbed to prototype new virtual machine technologies and experiment with different design alternatives. It runs on the Linux?/IA-32, AIX???/PowerPC???, OSX/PowerPC, and Linux/PowerPC platforms, and exhibits industry-strength performance for many benchmark programs on these platforms.

The WabaVM has been tested extensively for robustness. In its first release, making it robust was the top priority. If you experience any problems, please email support with the full description of the problem.

Some competing vendors will try to convince you with carefully selected benchmarks intended to prove the superiority of their solution. Don't be fooled. The only reliable way to determine performance in the real world, is to try for yourself. Real world applications are far more complex in their content and in their interaction with their external environment than can ever be captured in a simple execution benchmark.

The KVM is a specification for a Java Virtual Machine optimized for devices with limited resources such as cellphones, handhelds, or set-top boxes. For more details, see the white paper from Sun.

The CLDC specification was developed within the Java Community Process[sm] (JCP[sm]) program in collaboration with over 500 partners representing the wireless handset, service provider, and point of sale terminal industries. It outlines the most basic set of libraries and virtual machine features that must be present in each implementation of a Java 2 Platform, Micro Edition (J2ME[tm]) environment on resource-constrained devices.

The CLDC configuration was designed to bring the many advantages of the Java platform to connected devices that are limited in available resources. Targeted devices include cellular phones, pagers, mobile point-of-sale terminals, and any other device constrained in processing power, memory, and graphical capability.

The CLDC reference implementation (RI) provides a reference design that demonstrates how the CLDC specification can be implementated, and validates the Technology Compability Kit (TCK) that accompanies the specification. The CLDC RI provides a base which can be ported to different platforms by device manufacturers. It also provides a working environment which allows developers to test their CLDC-based applications against.

Popular CLDC-based devices that are shipping today include cellular phones and pagers. Most of these devices also rely on MIDP to complete the J2ME environment. For a list of current J2ME licensees please refer to: Java Authorized Licensees of J2ME. You can also refer to the J2ME Device page for a sample of popular J2ME devices that are in the market today. Unless otherwise licensed, code in all technical manuals herein (including articles, FAQs, samples) is provided under this License.

Use the latest, greatest, fastest JVM you can get your hands on for your platform. The compiler's performance is dependent on the performance of the JVM it is running on, so the faster a JVM you can find to run it on, the shorter your compile times will be. At a minimum you need to use a Java 2 or later JVM to run the compiler (J2SE 1.3 for AspectJ 1.1). We realize that this constraint can be a problem for users who don't currently have a Java 2 JVM available.