Today we are participants in the new age of information access and consumption for personal and business use. New types of information and new ways of using it are driving up demand for anytime and anywhere access, feeding a need for always-on and always-connected devices. Connectivity changes everything!

This is nowhere more evident than in systems that combine the new generation of smart embedded devices with powerful end-to-end services that integrate smart things to better serve and simplify the user’s environment. Deployment of these services involves a level of complexity that many embedded developers may not have dealt with before. These devices are found everywhere – in the pocket or purse, in the car, in the home, and of course in the office. They are symbols of the next generation of Net-centric computing and communications convergence.

They must be small, powerful, flexible, easy to use, secure, and affordable. They must integrate well with the existing infrastructure, work well with legacy devices, and support an easy and painless forward migration. They will have a short life span, followed closely by the next product, and therefore must be brought to market quickly, on time, and on budget.

Why Embedded Linux?
Embedded Linux delivers the reliability, openness, and performance required by the new generation of smart devices. This helps the development team quickly embrace embedded platform technology, allowing them to start by focusing on the unique requirements of deploying applications on compact connected things. Embedded Linux also provides access to the widest number of processor architectures and board implementations, allowing more flexibility in the choice of a deployment platform. When properly adapted for embedded applications, Linux offers the project manager and developer the best option on which to build embedded solutions. As the core Linux technology evolves to address new requirements, the infrastructure continues to grow, providing support for numerous new devices, technologies, protocols, and services. This work addresses the driver development and integration necessary to fully support the features and functions of a board. Most deployment platforms are custom made, based on a standard architecture and reference board. With access to the source code, Linux facilitates this approach, making it possible to develop several generations of a product family taking advantage of the evolution of the hardware technology over time.

With modern embedded Linux distributions, using a standard PC-based host for application development and testing is powerful and efficient. Cross development support allows programmers to build and test code running on the target platform while connected to the host platform. This facilitates rapid test and debug cycles resulting in much shorter time-to-market projects.

Why Embedded Java?
With all of the facilities and flexibility available from embedded Linux today, it might seem that using embedded Java for the applications is not necessary.

Java technology offers embedded systems developers some clear advantages over current alternatives such as C and C++ or assembler. The most significant are ease of development and maintenance, the facility to reuse code, easy integration with the native system when necessary, and availability of a large number of developers.

Java has been very successful over the past few years in the world of client-server applications, and more recently in the burgeoning e-commerce application server market. The focus in this space has led to many innovations that have benefited Java as an application environment – many that apply equally well to embedded applications as to server applications.

Development and Maintenance
Over the entire life of a project, the Java environment enhances ease of development and maintenance. When the target system is based on a virtual machine, code is easier to instrument, debug, analyze, hot-replace, and maintain. Network-enabled connected devices can be far more complex than previous kinds of embedded systems. Manual techniques for upgrading may no longer be effective over the project life cycle. Instead, the connectivity of devices provides the ability to manage components remotely, allowing development teams to add product features, resolve problems, and maintain and upgrade the software in the device after the product ships.

Java is a network-centric technology, designed and developed to support the notion that "the network is the system." Therefore it readily supports multiple network topology models, facilitates interoperability through its API standardization, and enables the delivery of features and services locally or via remote network services.

Java technology makes true cross development possible. Program function is developed on workstations, unit tested, and prepared for integration. Thus, even without access to prototype hardware, developers can proceed with function development. After prototype hardware is available, developers can share it through network attachments, creating a virtual lab accessible to team members within a company or among partner companies.

The Java program execution environment also reduces issues relating to memory management, allowing automated "garbage collection" techniques to be used to clean up after released memory segments.

Java Development Tools
Many developers and engineers have discovered that a critical advantage is gained when a complete toolkit is available to embedded Java application developers. Many of these developers have come to embedded projects from past experience deploying enterprise-class projects, and will focus on the logical extension of existing online services directly to pervasive connected embedded devices. These developers expect to find efficient development tools. They regularly use integrated development environments, sophisticated debuggers, ahead-of-time Java language compilation techniques, and program analysis profile tools. Most also have experience with integrated version control and release management facilities. There are many popular examples of Java development environments available today, including JBuilder from Borland and Forte from Sun. A completely integrated, cross-development environment, designed to support the developer working on the host and the target, is often the critical factor in helping a project stay on time. VisualAge Micro Edition from IBM/OTI is the leading example today.

Many developers working to create embedded Java applications using an embedded Linux operating system will also want to use Linux as their development workstation. This helps create a uniform and efficient development experience and avoids the necessity of switching between Linux and Windows workstation conventions for commands and user interface interaction. IBM has provided the VisualAge Micro Edition IDE and tools for use on Red Hat Linux–based developer workstations. This supports a complete cross-development embedded experience for engineers and developers.

It’s often an advantage to develop applications on a personal computer workstation and then deploy them remotely to connected devices in a shared laboratory. The VisualAge Micro Edition tools provide this through remote debugger and program analysis tools and the use of shared file techniques between the developer workstation and the target platform. NFS- or LAN-based sharing techniques permit a Java program object to be immediately loaded on a remote device.

With the hot-code replacement facilities of the virtual machine, program changes can be immediately and seamlessly activated from the debugger interface on the developer workstation. This tight integration leads to a new level of efficiency for embedded developers. Since Java technology is based upon virtual machine technology, hot-code replacement is available to connected embedded devices. This offers a new degree of flexibility and convenience to the designers of embedded projects. In particular, it’s possible to design future enhancements and feature activation based upon these techniques using OSGi Bundle Management. This article is part of Michael Mathews' feature in the next issue of LinuxWorld Magazine. To read more about embedded Linux with Java, be sure to pick up the November/December issue of LWM!