Real-time Java: Difference between revisions

Revision as of 13:54, 17 November 2005

Revision as of 23:53, 23 November 2005

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[[Java]] supported threaded [[programming]] from the very beginning.

{{cleanup-date|November 2005}}

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==Real Time System?==

Java supported threaded programming from the very beginning. However, itIt was not immediately suitable for [[Real time]] systems for two critical reasons:

1)* The threading behavior was largely unspecified. This, reputedly, was a concession to [[Microsoft]] to allow for the weak threading models underlying the [[Windows]] operating system at the time.

2)* More critically, the [[garbage]] collector behavior introduces unbounded delays in [[computation]], immediately destroying any chance of making real-time guarantees for programs written in [[Java]].

==The Java Programming Language==

Because [[Java]] is such an elegant language for [[programming]], and because it supports [[threading]] generally and several [[language]] features that promote correcntness, it is a good prospect for real-time systems. To produce a specification for [[Java]] that would allow its use in such environments, [[JSR001]] was created. As of 2005, a number of implementations of the resulting Real-Time Specification for [[Java]] (RTSJ) have emerged, including a reference implementation (from [[Timesys]], I think) and a full fledged product from [[Sun Microsystems]].

The RTSJ addresses the critical issues by mandating a minimum specification for the threading model (and allowing other models to be plugged into the VM) and by providing for areas of [[memory]] that are not subject to garbage collection, along with threads that are not preemptable by the garbage collector.

In addition, many other enhancements to the [[Java]] system have been included resulting in a specification that provides realistic support for writing real-time systems in [[Java]].

[[Category:Java]]