1z0-599 Oracle WebLogic Server 12c Essentials Questions and Answers

Note:

-DserverType={"wls" | "wlx"}

Specifies the Server Type, which determines the set of services that are started in the server runtime.

The default is "wls", which starts all WebLogic Server services, including EJB, JMS, Connector, Clustering, Deployment, and Management.

The "wlx" option starts a server instance that excludes the following services, making for a lighter weight runtime footprint:

* (not D) Enterprise JavaBeans (EJB)

* (not B, not E) Java EE Connecter Architecture (JCA)

* (not C) Java Message Service (JMS)

The major components of the WebLogic JMS Server architecture, as illustrated in the figure below.

*(A) JMS servers that can host a defined set of modules and any associated persistent storage that reside on a WebLogic Server instance.

*(B) JMS modules contains configuration resources (such as queues, topics, and connections factories) and are defined by XML documents that conform to the weblogic-jmsmd.xsd schema.

*Client JMS applications that either produce messages to destinations or consume messages from destinations.

*(E) WebLogic persistent storage (file store or JDBC-accessible) for storing persistent message data.

The following figure illustrates the WebLogic JMS architecture.

Note:

* Persistent messages are saved in the persistent store on the sending side until they are successfully forwarded to and acknowledged by the receiving side.

Note:

* It is recommended that you shutdown WebLogic Server instances through the Administration Console.

* If automatic server migration is enabled, the servers are required to contact the cluster leader and renew their leases periodically. Servers will shut themselves down if they are unable to renew their leases. The failed servers will then be automatically migrated to the machines in the majority partition.

Note:

*A multi data source can be thought of as a pool of data sources. Multi data sources are best used for failover or load balancing between nodes of a highly available database system, such as redundant databases or Oracle Real Application Clusters (Oracle RAC).

* (not B)A single GridLink data source provides connectivity between WebLogic Server and an Oracle Database service, which may include multiple Oracle RAC clusters

* High Availability Storage Solutions

If you have applications that need access to persistent stores that reside on remote machines after the migration of a JMS server or JTA transaction log, then you should implement one of the following highly-available storage solutions:

/ File-based stores (default or custom)—Implement a hardware solution, such as a dual-ported SCSI disk or Storage Area Network (SAN) to make a file store available from shareable disks or remote machines.

/ JDBC-accessible stores—Configure a JDBC store or JDBC TLOG store and use JDBC to access this store, which can be on yet another server. Applications can then take advantage of any high-availability or failover solutions offered by your database vendor. In addition, JDBC stores support GridLink data sources and multi data sources, which provide failover between nodes of a highly available database system, such as Oracle Real Application Clusters (Oracle RAC).

A:

* Troubleshooting Slow Response Time from the Client and Low Database Usage

These symptoms are usually caused by a bottleneck upstream of the database, perhaps in the JDBC connectionpooling. Monitor the active JDBC connections in the WebLogic Console and watch for excessive waiters and wait times; increase the pool size, if necessary.

* Attribute: Maximum Capacity

Maximum number of physical database connections that this connection pool can contain. Different JDBC Drivers and database servers may limit the number of possible physical connections.

C: Attribute: Statement Cache Size

The algorithm used to maintain the statement cache:

LRU - After the statementCacheSize is met, the Least Recently Used statement is removed when a new statement is used.

Fixed - The first statementCacheSize number of statements is stored and stay fixed in the cache. No new statements are cached unless the cache is manually cleared.

E: If the queue appears starved but adding execute threads does not improve performance,

there may be resource contention. Because CPU utilization is low, the threads are probably

spending much of their time waiting for some resource, quite often a database connection.

Use the JDBC monitoring facilities in the console to check for high levels of waiters or long

wait times. Adding connections to the JDBC connection pool may be all that is required to

fix the problem.

Note:

* If you had a JDBC connection pool where the Initial Capacity and Maximum Capacity attributes were different, you might want to create a gauge monitor to monitor the maximum and minimum number of connections.

By setting the Threshold Low value to be one less than the Initial Capacity, your gauge monitor trapcould monitor the ActiveConnectionsCurrentCount attribute of the JDBCDataSourceRuntime MBean and alert you whenever the number of active connections are less than the Initial Capacity (which might indicate database connectivity problems).

A:

* The WEB-INF directory contains the deployment descriptors for the Web application (web.xml and weblogic.xml) and two subdirectories for storing compiled Java classes and library JAR files.

* Web Application - WEB-INF/web.xml ( WEB-INF/weblogic.xml )

The WEB-INF directory is a vital component of your web application. Web application wont run without it.It contains a heirarcy in which you’ll find the necessary configuration information for your web application, and all the class files for your servlets and classes that are called up by your JSPs.

WEB-INF folder contains all the class files for your servlets and classes that are called up by your JSPs

B:

Enterprise Application - META-INF/application.xml (META-INF/weblogic-application.xml) and META-INF/ejb-jar.xml ( META-INF/weblogic-ejb-jar.xml )

Generally comprises of EJBs. Bussiness Tier of an application and EJB basically handels the Bussiness logic of application (distributed objects)

META-INF/application.xml containes Mappings and security roles etc.whereas META-INF/ejb-jar.xml containes ejb classes , session beans mapping etc.,

The META-INF directory is related to .jar files, It contains the manifest file which has list of jars.

A context-root setting in application.xml takes precedence over context-root setting in weblogic.xml (The context root of a web application determines which URLs weblogic will delegate to your web application.

Note:

* Deployment descriptors are xml documents that describe runtime behaviour for the deployment unit. The XML file contains information such as the context root of the web application and the mapping of the portable names of an application's resources to the application Server's resources