Weblogic Interview Questions & Answers
Q: – How do I increase WebLogic Server memory?
Increase the allocation of Java heap memory for WebLogic Server. (Set the minimum and the maximum to the same size.) Start WebLogic Server with the -ms32m option to increase the allocation, as in this example:
$ java … -ms32m -mx32m …
This allocates 32 megabytes of Java heap memory to WebLogic Server, which improves performance and allows WebLogic Server to handle more simultaneous connections. You can increase this value if necessary.
Q: – Can I start a Managed Server if the Administration Server is unavailable?
By default, if a Managed Server is unable to connect to the specified Administration Server during startup, it can retrieve its configuration by reading a configuration file and other files directly. You cannot change the server's configuration until the Administration Server is available. A Managed Server that starts in this way is running in Maindex index managed Server Independence mode.
Q: – How are notifications made when a server is added to a cluster?
The WebLogic Server cluster broadcasts the availability of a new server instance each time a new instance joins the cluster. Cluster-aware stubs also periodically update their list of available server instances.
Q: – What happens when a failure occurs and the stub cannot connect to a WebLogic Server instance?
When the failure occurs, the stub removes the failed server instance from its list. If there are no servers left in its list, the stub uses DNS again to find a running server and obtain a current list of running instances. Also, the stub periodically refreshes its list of available server instances in the cluster; this allows the stub to take advantage of new servers as they are added to the cluster.
Q: – Can I enable requests to a JDBC connection pool for a database connection to wait until a connection is available?
No, there's no way to allow a request to wait for a pool connection, and from the system point of view there should not be. Each requests that waits for a connection ties up one of the fixed number of execute threads in the server, which could otherwise be running another server task. Too many waiting requests could tie up all of the execute threads and freeze the server.
Q: – How do I use multibyte character sets with WebLogic jDriver for Informix?
Currently, multibyte character sets are not supported for the WebLogic jDriver for Informix driver.
Q: – Can I configure the messaging bridge to automatically downgrade the quality of service if the Exactly-once service isn't available on either the source or target bridge destination?
Yes, just make sure to select the QOS Degradation Allowed check box on the Messaging Bridge > Configuration > General administration console page.
Q: – How do I restrict access to servlets and JSPs?
The Java Servlet API Specification v2.2 allows you to declaratively restrict access to specific Servlets and JSPs using the Web Application Deployment descriptor. Section 13.3.2 of the specification has an example deployment descriptor that uses declarative security. For more information, see Programming WebLogic HTTP Servlets.