SlimVM: a small footprint Java virtual machine for connected embedded systems

The usage of cellular phones, PDAs, and other mobile devices has increased dramatically over the past ten years. Java is targeted to be one of the most popular execution environments on such systems. However, since mobile devices are inherently limited in terms of local storage capacity and Java requires large amounts of library code to be present on each client device, it is crucial to reduce the code and memory footprint to ensure Java's success on such systems. SlimVM's approach eliminates all unnecessary code and meta information on mobile devices. We present a solution for the next generation of mobile computing environments for persistent connected embedded systems where all code resides on a network server and is requested at run time by the Java virtual machine on the client. All application and library code is analyzed on the server prior to execution on the mobile device, and only code essential for execution is sent to the client on demand. Java bytecode is manipulated and transferred to the client in the form of pre-linked basic blocks. Measurements show a reduction of the memory footprint of up to 70%.