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Date: Thu, 03 Mar 2011 16:58:53 -0500
From: Hyman Rosen <hyrosen@mail.com>
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Subject: Re: Air traffic control system in Java
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Date: 2011-03-03T16:58:53-05:00
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On 3/3/2011 4:44 PM, Vinzent Hoefler wrote:
> Did you know that not even the scheduling is defined by the language,
> although Java threads sure can have a priority assigned? Yet, there's
> no guarantee that the highest priority task will even run.

This sounded false to me, so I looked:
<http://www.ibm.com/developerworks/java/library/j-rtj1/index.html>

     The Real-time Specification for Java

     With the RTSJ, true priorities and a fixed-priority preemptive
     scheduler with priority-inheritance support is required for RT
     threads. This scheduling approach ensures that the highest-
     priority active thread will always be executing and it continues
     to execute until it voluntarily releases the CPU or is preempted
     by a higher-priority thread. Priority inheritance ensures that
     priority inversion is avoided when a higher-priority thread needs
     a resource held by a lower-priority thread.