1.1 Configurations and Profiles
1.1.1 Architecture
J2ME is the newest and smallest addition to the Java family. It is the smaller brother of J2SE (Standard Edition) and the server-based J2EE (Enterprise Edition). As mentioned, J2ME provides a development environment for a range of small, constrained devices. Even though J2ME is targeted at devices with limited capabilities, it has been derived from J2SE and shows all the characteristics of the Java language. We have already introduced the concepts of configurations and profiles; the rest of this chapter will explain how and why these concepts have been derived and implemented.
Each combination of configuration and profile matches a group of products specifically optimized to match the memory, processing power and I/O capabilities of each device.
The full Java architecture can be seen in Figure 1.1. It shows how the technology has developed to offer a platform for a range of circumstances. Enterprise applications can be developed using the J2EE packages, taking full advantage of the power of large servers capable of transmitting large chunks of data across networks. The J2SE edition complements J2EE and provides the basis for desktop-type applications. Already we can see that these two versions of Java are defined with consideration of processor
power, memory and communication ability: it would be inefficient for the virtual machine running on a desktop machine (J2SE) to also include large packages targeted towards an enterprise application (J2EE).
Further inspection of the Java architecture reveals that there are two groups of special interest to us, under the banner of J2ME. J2ME provides an environment for developers wishing to develop applications for smaller devices. This environment has been specialized to cater for machines with even less capacity.
1.1.1 Architecture
J2ME is the newest and smallest addition to the Java family. It is the smaller brother of J2SE (Standard Edition) and the server-based J2EE (Enterprise Edition). As mentioned, J2ME provides a development environment for a range of small, constrained devices. Even though J2ME is targeted at devices with limited capabilities, it has been derived from J2SE and shows all the characteristics of the Java language. We have already introduced the concepts of configurations and profiles; the rest of this chapter will explain how and why these concepts have been derived and implemented.
Each combination of configuration and profile matches a group of products specifically optimized to match the memory, processing power and I/O capabilities of each device.
The full Java architecture can be seen in Figure 1.1. It shows how the technology has developed to offer a platform for a range of circumstances. Enterprise applications can be developed using the J2EE packages, taking full advantage of the power of large servers capable of transmitting large chunks of data across networks. The J2SE edition complements J2EE and provides the basis for desktop-type applications. Already we can see that these two versions of Java are defined with consideration of processor
power, memory and communication ability: it would be inefficient for the virtual machine running on a desktop machine (J2SE) to also include large packages targeted towards an enterprise application (J2EE).
Further inspection of the Java architecture reveals that there are two groups of special interest to us, under the banner of J2ME. J2ME provides an environment for developers wishing to develop applications for smaller devices. This environment has been specialized to cater for machines with even less capacity.
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