1.3 A Bit of History
The Java programming language was initially targeted towards consumer devices, especially the interactive TV market. However, over time the Java platform evolved more and more towards the needs of desktop and enterprise computing. Enterprise applications generally require rich library functionality, and over time the Java libraries grew larger and more comprehensive to cater better to the needs of the enterprise market and large server-side applications. However, this evolution made the libraries too large and unsuitable for the majority of small, resource-constrained devices.
In January 1998, the Spotless project was started at Sun Microsystems Laboratories (Sun Labs) to investigate the use of the Java programming language in extremely resource-constrained devices. The research goal of the project was to build a Java runtime environment that would fit in less than one-tenth of the typical size. At the implementation level, the goal was to build a Java virtual machine with the following characteristics:
Small size is important, since the majority of wireless, mobile devices (for example, cell phones) are still very resource-limited and often have only a few tens or hundreds of kilobytes of memory available for applications. Portability, ease of use, and the readability of the source code are equally important. Most embedded device manufacturers need to support dozens or even hundreds of different hardware configurations that run on several different hardware platforms, and it would be not only tedious but also very expensive to spend a lot of time porting and customizing the Java platform implementation to all those hardware configurations and platforms. Also, embedded device manufacturers cannot generally be expected to be experts on the Java programming language or virtual machine. Therefore, the easier the implementation is to understand and use, the faster the device manufacturers will deploy it across their devices.
Even though the Spotless effort was initially a research project, the project group established active contacts with external customers early on. External customers, especially Motorola, played a significant role in convincing Sun to turn the Spotless system from a research project into a commercial product. The product version of the Spotless virtual machine is known today as the K Virtual Machine (KVM). The Spotless system is documented in the Sun Labs technical report The Spotless System: Implementing a Java System for the Palm Connected Organizer (Sun Labs Technical Report SMLI TR-99-73).
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