Red Hat Application Server, Manual

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Chapter 1. Java Open Application Server (JOnAS): a J2EE Platform 13
In addition to clustering solutions, JOnAS provides many intrinsic mechanisms to ensure high scalable
and efficiency:
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A pool of stateless Session Bean instances
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A pool of Entity Bean instances, configurable for each Entity Bean within its deployment descriptor
•
Activation/passivation of entity beans (passivation can be controlled through the management con-
sole)
•
Pools of connections, for JDBC, JMS, J2EE CA connectors
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A pool of threads for message-driven beans
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Session Bean timeout can be specified at deployment
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A “shared” flag in the specific deployment descriptor of an Entity Bean that indicates whether the
persistent representation of this Entity Bean is shared by several servers/applications, or whether it
is dedicated to the JOnAS server where it is loaded. In the latter case, the optimization performed
by JOnAS consists of not reloading the corresponding data between transactions.
•
The usual EJB 1.1 “isModified” (or “Dirty”) mechanism is available, for avoiding storage of un-
modified data.
Some benchmarks and JOnAS Use cases have already proven that JOnAS is highly scalable. Re-
fer to the Rubis http://www.cs.rice.edu/CS/Systems/DynaServer/perf_scalability_ejb.pdf results or the
OpenUSS Use case (http://openuss.sourceforge.net/openuss/). Rubis is a benchmark for e-commerce
J2EE applications, which now belongs to the ObjectWeb JMOB (Java Middleware Open Benchmark-
ing) project (http://www.objectweb.org/jmob/index.html). OpenUSS is an operational university por-
tal that has approximately 20,000 users.
1.6. Future Development
As an open source implementation of a J2EE server, JOnAS is constantly evolving to satisfy user
requirements and to follow the related standards. These are the current JOnAS plans:
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J2EE 1.4 compliance, JOnAS being currently in the process of passing the Sun J2EE Compatibility
Test Suite.
•
JOnAS administration will be enhanced by completing the concept of management domain, and by
introducing cluster management facilities.
•
Addressing performance issues by developing workbenches and by producing tuning guides.
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Support of “Web Services” and tools for developing those services.
•
Deployment APIs as specified in JSR88 (J2EE 1.4) will be supported as a result of the Ishmael
project.