Real-time Java: Difference between revisions

Revision as of 17:50, 4 May 2025

Revision as of 20:49, 9 July 2025

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* event handling.

The initial proposal<ref>{{Cite web| title=Issues in the Design and Implementation of Real-Time Java | url=http://www.cs.cornell.edu/courses/cs614/1999sp/papers/rtji.pdf | archive-url=https://web.archive.org/web/20170809011950/http://www.cs.cornell.edu/courses/cs614/1999sp/papers/rtji.pdf | archive-date=2017-08-09}}</ref> for an open standard for real-time Java was put forth by Kelvin Nilsen, then serving as a research faculty member at Iowa State University. A follow-on overview paper was published in the ''[[Communications of the ACM]]''.<ref>{{cite journal | url=https://dl.acm.org/doi/abs/10.1145/276609.276619 | doi=10.1145/276609.276619 | title=Adding real-time capabilities to Java | date=1998 | last1=Nilsen | first1=Kelvin | journal=Communications of the ACM | volume=41 | issue=6 | pages=49–56 }}</ref> The overwhelmingly positive response to these early proposals resulted in a series of meetings hosted by the National Institute of Standards and Technology in an effort to establish an open standard for real-time Java. NIST was ultimately told that they were not the appropriate body to establish standards related to the Java language, as Java was trademarked, and the technologies were owned by Sun Microsystems. Therefore, NIST ended their efforts with publication of consensus requirements.<ref>{{cite journal | url=https://www.itl.nist.gov/div897/ctg/real-time/rtj-final-draft.pdf | title=Information Technology Laboratory | journal=NIST | date=28 April 2015 }}</ref> that could be considered by future standardization efforts to be hosted by Sun Microsystems.

When the [[Java Community Process|Java Community]] was formed, the very first effort was the specification for real-time Java, JSR001. A number of implementations of the resulting ''Real-time specification for Java'' (''RTSJ'') have emerged, including a [[reference implementation (computing)|reference implementation]] from [[TimeSys|Timesys]], [[IBM]]'s WebSphere Real Time, [[Sun Microsystems]]'s Java SE Real-Time Systems,<ref>{{Cite web|url=http://java.sun.com/javase/technologies/realtime/index.jsp|title=Sun Java Real-Time System|website=java.sun.com}}</ref> PTC Perc from [[PTC, Inc.]],<ref>{{Cite web|url=http://www.ptc.com/developer-tools/perc|title=Real-Time Java with PTC Perc &#124; PTC}}</ref> or [[JamaicaVM]] from aicas.

The RTSJ addressed 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. These areas are instead managed using [[region-based memory management]]. The latest specification, 2.0, supports direct device access and deterministic garbage collection as well.

==Real-Time Specification for Java==

The ''Real-Time Specification for Java'' (RTSJ) is a set of [[Interface (computer science)|interface]]s and behavioral refinements that enable real-time [[computer programming]] in the [[Java (programming language)|Java programming language]]. RTSJ 1.0 was developed as JSR 1 under the [[Java Community Process]], which approved the new standard in November, 2001. RTSJ 2.0 is being developed under JSR 282. A draft version is available at a JCP page.<ref>https://www.jcp.org/en/jsr/detail?id=282 JSR 282</ref> More information can be found from Aicas.<ref>{{Cite web | title=Real-Time Specification for Java {{!}} aicas.com | url=https://www.aicas.com/cms/rtsj | archive-url=https://web.archive.org/web/20150526085240/https://www.aicas.com/cms/rtsj | access-date=2025-02-17 | archive-date=2015-05-26}}</ref>

==See also==