Freitag, Juli 23, 2004


Configure JVM for OC4J

When you update the JVM of OC4J you must also change following security parameters in the file to prevent a java.lang.SecurityException:   
In the standard JVM configuration the appropriated JVM security definition file will be located in:  /usr/java1.4.x/jre/lib/security/  



Dienstag, Juli 06, 2004


Support of Oracle Application Server Load Balancing Strategies

mod_oc4j Load Balancing support follow routing strategies:

route the request to next JVM in a cluster in usage of the randomm algorithm.

Random with local affinity
route the request to next JVM on the local machine in usage of the random algorithm, if none available
it reroute to the next remote JVM also in usage of the ramdom algorithm.

Random with routing weight
route each request randomly to all available JVM in a cluster depending of the
configured routing resource weight. A high value (integer) means more resources available.

Round robin
choose for each request the next JVM in a cluster.

Round robin with local affinity
prefer the for each request the next JVM on the locale mashine
other it will use the next remotely.

Round robin with routing weight
prefer the for each request the next JVM in a cluster depending of the
configured routing resource weight.

Metric based
choose the JVM based on OC4J metrics and his availability.

Metric based with local affinity
first choose the JVM based on locale OC4J metrics and his availability otherwise it will choose the JVM remotely.

See also ...

Montag, Juli 05, 2004


HTTP-Connection test with telnet

recently I get the question how to test a HTTP Server connection without any browser (eg. on a server without any X-Server). The simplest way is to connect the HTTP Server with the telnet programm and request the resource with HTTP commands:
Here an example:
Open the connetion with the http listener port:
telnet 80
Requet the resource /index.htm with GET methode and protocol HTTP/1.1:
GET /index.htm HTTP/1.1

This will get the complete html content of the index.html page


HEAD /pages/test.jsp HTTP/1.1
to get informations about the resource

See also ....

Sonntag, Juli 04, 2004


UIX: Build Context Relative Links

to build a resource URL including the context path you can use the ui:contextURI methode directly in your UIX-Page as follow:

<contents childData="${fileList.file} >
<link text="${uix.current.text}">
<boundAttribute name="destination">
<contextProperty select="ui:contextURI"/>
<fixed text="/"/>
<ui:dataObject source="${uix.current.source}"/>

Donnerstag, Juli 01, 2004


EJB Lookup within Oracle Appliaction Server in usage of Clustering, Scalability and Fault-Tolerance

There is a main different between OC4J-Standalone EJB addressing schema and OC4J integrated in the Oracle Application Server. Think, Oracle Application Server has additional features regarding Clustering, Scalability and Fault-Tolerance, witch must be carefully attended in the deployment and EJB calling phase.
E.g. for scalability you can instance more then one OC4J components with the same configuration (many OC4J processes). In this case you must configure (default) a RMI port range in the opmn.xml. So OPMN (Oracle Process Monitor) is able to assign a different port to each OC4J instance in the startup phase.
A other feature of Oracle Application Server is to load balance the EJB calls depending of many different implemented algorithm (eg. round robin, metric based, ...). In each of this cases you can not address an OC4J instance directly like this:

env.put(Context.PROVIDER_URL, "ormi://HOST:PORT/EjbAppName")

In this situation you should us the following addressing schema:

env.put(Context.PROVIDER_URL, "opmn:ormi://HOST:OPMNPORT:OC4JInstanceName/EjbAppName");

Notice: for application portability, Oracle recommends to use instead of hardcoding the environment properties in client code.

You will find more information regarding OC4J and EJB in the OC4J Service Guide and in the OC4J-FAQ on OTN


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