A deterministic response time is the most important and necessary feature in Hard Real-Time Systems. This is the main reason why some years ago it was unthinkable to implement Hard Real-Time Systems with the Java language, an object-oriented, interpreted language, mainly because Java uses garbage collection to implicitly deallocate dynamic memory; This is widely known as“the garbage collection problem''… in the Real-Time Systems community, due to its temporal unpredictability. Nevertheless, few years ago a new standard, known as RTJava, has been specified to transform the Java language into a Real-Time compliant one, making it possible to implement Real-Time applications in Java. This new Real-Time standard tries to benefit from the experience gained in the design of other Real-Time languages, taking advantage of their real-time properties like scheduling control. On the other hand, RTLinux is a Hard Real-Time Operating System which allows to implement Hard Real-Time applications while preserving all of the Linux functionalities available for the Soft Real-Time part of the application. This paper will describe how we have ported the JamVM, a free Java Virtual Machine implementation to run Java bytecode directly on RTLinux, which allows to benefit from both the capabilities of the Java language and the RTLinux OS. This work represents our first milestone in the more ambitious goal to provide an Real-Time RTJava platform based on RTLinux.

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