BEA WebLogic Server Frequently Asked Questions

 

Contents

 

1. FAQs: Administration and Configuration

What are safeguards for modifying the config.xml file?

How do I edit the config.xml file?

2. FAQs: Applets

What are the alternatives to using applets?

Can I use a "native" two-tier driver for a browser applet?

Why doesn't my browser applet connect to the database?

Why does my applet work with Appletviewer, but not with a browser?

What's causing ClassFormatErrors with my applet?

3. FAQs: Clustering

How do stubs work in a WebLogic Server cluster?

What happens when a failure occurs and the stub cannot connect to a WebLogic Server instance?

How does a server know when another server is unavailable?

How are notifications made when a server is added to a cluster?

How do clients learn about new WebLogic Server instances?

How do clients handle DNS requests to failed servers?

How many WebLogic Servers can I have on a multi-cpu machine?

Should I use a separate network for multicast in a cluster?

4. FAQs: Code Examples

Why can't I run an example class file with the java classname command?

How do I use the Cloudscape evaluation version with the EJB examples?

5. FAQs: dbKona

How are JDBC and dbKona related?

Does dbKona use vendor-specific native libraries to communicate with a remote DBMS?

How does performance compare between dbKona and raw SQL through JDBC?

What happens to a dbKona TableDataSet when I save changes?

6. FAQs: EJB

Why did my JDBC code throw a rollback SQLException?

Must my bean-managed persistence mechanism use the WebLogic JTS driver?

Why is there no polymorphic-type response from a create() or find() method?

Must EJBs be homogeneously deployed across a cluster? Why?

7. FAQs: Installation

How do I access and download Service Packs?

If I've already downloaded WebLogic Server, how can I upgrade when a new Service Pack is released?

How do I install Service Packs?

How do I view and recover files replaced or deleted by a Service Pack installation?

My Service Pack installation failed. Why did I receive this message: Java 1.3 and up is required?

How do I confirm that the Service Pack has been applied?

Can I apply the Service Pack to my Beta version of WebLogic Server 6.0?

Why isn't the Service Pack installer finding my installation of WebLogic Server?

How do I download and install WebLogicServer 6.0 for Compaq Tru64 Unix using the WinZip file?

8. FAQs: Java

Can you help me debug my program?

Where can I get help learning Java?

Where do I get the JDK?

How do I set up my CLASSPATH?

Why won't the examples work?

Where can I get help with Java error messages?

Why did a client-server message generate a StackOverflowException?

Will a JIT make my Java application run faster?

Can I redistribute the JDK that is bundled with WebLogic Server?

9. FAQs: WebLogic JDBC

When should I use MultiPools?

How can I tell if a database is unavailable?

10. FAQs: WebLogic jDriver for Informix

How do I use multibyte character sets with WebLogic jDriver for Informix?

How do I allow multiuser access to my Informix database?

11. FAQs: WebLogic jDriver for Oracle

Why does FOR UPDATE in Oracle 8 cause an ORA-01002 error?

What causes an OCIW32.dll error?

What transaction isolation levels does the WebLogic jDriver for Oracle support?

How do I use Unicode codesets with the WebLogic jDriver for Oracle driver?

How do I use OS Authentication with WebLogic jDriver for Oracle and Connection Pools?

What type of object is returned by ResultSet.getObject()?

How do I limit the number of Oracle database connections generated by WebLogic Server?

How do I call Oracle stored procedures that take no parameters?

How do I bind string values in a PreparedStatement?

Why do I get unexpected characters from 8-bit character sets in WebLogic jDriver for Oracle?

How do I learn what codesets are available in Oracle?

How do I look up an "ORA" SQLException?

What is error "ORA-6502?"

Why do I get an error while trying to retrieve the text for ORA-12705?

Why do I run out of resources during updates with Oracle's database link?

How do I prevent errors when running t3dbping?

12. FAQs: JMS

What makes WebLogic JMS unique?

How has JMS changed between releases 5.x and 6.0?

What JMS features are new in WLS 6.1?

What problems were fixed in WLS 6.0 Service Pack 1 and what known problems still exist?

Can WLS 5.X JMS clients talk to WLS 6.X or vice versa?

Are there C/C++ interfaces to WLS JMS?

Is there a smaller version of weblogic.jar for supporting clients?

Where can I learn more about JMS?

What are the relationships between the various JMS objects in WLS 6.0?

How do I start WLS and configure JMS?

How do I configure JMS security?

Can I still use the default connection factories supported in WebLogic Release 5.1?

Why does JMSSession.createTopic or JMSSession.createQueue fail to create a destination in WLS JMS 6.0 (it worked in 5.1)?

How do I programmatically get a list of Queues or Topics?

How do I use a temporary destination?

How do I use MBeans to print runtime statistics?

Can two JMS servers share the same persistent store?

Which types of JDBC databases does WebLogic JMS support?

How do I use a third-party JDBC driver with JMS?

What if my JDBC database becomes corrupt?

How do I use persistence?

How does a file store compare with a JDBC store?

How do the WLS JMS 6.0 server/destination message maximum and threshold values work?

How do I configure JDBC so that the JMS JDBC Store recovers automatically?

Does WebLogic JMS support clustering?

How can I control on which WebLogic Server(s) my application will run?

What is the value of JMS clustering in WLS 6.0?

How do I perform a manual fail-over?

Does the WLS JMS server find out about closed or lost connections, crashes, and other problems and does it recover from them?

Do I need to use the WLS T3 protocol?

How do I do HTTP tunneling?

Does WLS JMS support SSL?

How do I integrate non-WLS JMS providers with WLS?

How do two-phase or global transactions relate to WebLogic JMS?

Why is my JMS work not part of a user transaction (i.e., called within a transaction but not rolled back appropriately)? How do I track down transaction problems?

How can an application do a JMS operation and have it succeed, independent of the result of the transaction?

What happens if acknowledge() is called within a transaction?

Why do I get an error when using a non-transacted TopicSession from a transaction-required EJB?

Can I use a one-phase commit if my JMS JDBC store is on the same database for which I am doing other database work?

How do I integrate an XAResource with WLS to get JTA transactions with another resource manager?

Why do I get an exception when I start up JMS using an XA driver or with a TX data source?

Is WLS JMS XAResource compliant?

Why can't I receive a message that I send within a container-managed transaction?

What happens to a message that is rolled back or recovered?

Is it possible to set aside a message and acknowledge it later?

How should I use sorted queues?

How does sorting on message priority work?

How do I deal with a listener that doesn't keep up with messages being sent?

How do I get a thread dump to help track down a problem?

Do client identifiers need to be unique?

Are messages passed by copy/value or reference?

How do I manage a queue to view and delete specific messages?

How do I close a queue so that the messages will not be reloaded at the next server startup?

Why does an Object Message print as null after it is received?

In what order are messages delivered to a consumer?

Why do I get an exception when trying to find a connection factory?

Why should I avoid using selectors?

Is it possible to have multiple queue receivers listening on the same queue, using MessageSelectors (typically filtering on a correlation ID) to determine which listener actually receives the message?

Is there a way to make a queue such that if one application has one object as listener on that queue, no other application can listen to the messages on that queue?

Why don't setting values work using javax.jms.Message.setJMSPriority, DeliveryMode, Destination, TimeStamp or Expiration?

What care must be taken when multi-threading JMS clients?

How should an application be set up to subscribe to multiple topics?

How should I use blocking and asynchronous receive() calls?

What precautions should I take when I use blocking receive() calls?

What is the NO_ACKNOWLEDGE acknowledge mode used for?

When should I use multicast subscribers?

When should I use server session pools and connection consumers?

How do I issue the close() method within an onMessage() method call and what are the semantics of the close() method?

How do I publish an XML message?

How do I use JMS in an applet?

How do I use a startup class to initialize and later reference JMS objects?

Is it possible to send or receive a message from within a message listener?

How do I create a producer pool?

What are pending messages in the console?

How do I use a less than or greater than on a message selector in ejb-jar.xml?

Is it better to have more or fewer sessions for a given number of subscribers?

Are foreign destinations handled within foreign JMS messages?

What is the standard way to create threads, do initialization, etc. within the application server?

Why do I get a JNDI problem when I name a Topic A.B and a second Topic A.B.C?

How many messages are sent across the network for processing topic messages?

What should an XPATH selector look like?

How do I handle request/response using JMS?

How do I put a message back on the queue for processing?

Is it OK to add new sessions and subscribers to a Queue or Topic Connection once it has been started?

What can I do when I get java.lang.OutOfMemoryError because producers are faster than consumers?

Why have different connection factories?

How should connections and sessions be allocated?

How does an application know if an application server goes down?

How do I debug WebLogic Server using Visual Cafe 4.1?

Is there a way to dynamically change an existing selector for a TopicConsumer using setMessageSelect(String s)?

How can I avoid asynchronous message deadlocks?

What are the advantages of message-driven beans?

How does concurrency work for message-driven beans?

Can an MDB be a message producer or both a producer and consumer?

If an MDB uses a durable subscription, will messages be accumulated if the MDB is not deployed?

How do I use non-WebLogic Server JMS provider destinations to drive MDB's?

Can you use a foreign JMS provider to drive an MDB transactionally?

How do I use JTA transactions within an MDB?

How do server session pools and message driven beans compare?

13. FAQs: JTA

Can I use a non-XA driver in distributed transactions?

Can I use more than one non-XA connection pool in distributed transactions?

How do XA and non-XA drivers differ in distributed transactions?

What XA drivers can I use in addition to the WebLogic jDriver for Oracle/XA?

Can I use the Oracle thin driver as an XA driver in distributed transactions?

Do I need a 2PC licence when I use JMS with one JDBC non-XA driver?

Why am I getting an exception when I use JMS with a non-XA driver?

Why do I get an exception when I use EJB CMP 1.1?

Can I obtain a JDBC connection before I start a distributed transaction?

Can I close a JDBC connection after the distributed transaction is committed or rolled back?

14. FAQs: Security

How can I update my demonstration digital certificates and trusted CAs?

Why does the servlet return "no certificate"?

Does WebLogic support Diffie-Hellman or DSS/DSA digital certificates?

Can the server have one RSA and one non-RSA certificate?

Must we pay RSA licensing costs for non-RSA client code?

How do I use Netscape security certificates with WebLogic Server?

How do I restrict access to servlets and JSPs?

Can I use RSA encryption algorithms and javax.crypto.* API to build applications?

Can I use a JNDI Initial Context to pass the security credentials of a WebLogic Server user?

15. FAQs: Server-Related Questions

How do I configure WebLogic to use a SOCKS proxy?

How can I speed up connection responses?

How does WebLogic support CORBA and client communication via IIOP?

How do I speed up HTTP tunneling?

Can WebLogic Server start with a UNIX boot?

What affects servlet performance besides clients and traffic?

Why do I get "NoClassDefFound"/"Too Many Open files"messages on Solaris?

How do I increase WebLogic Server memory?

What causes Java.io exceptions in the log file?

Java-CORBA integration: RMI-IIOP or Java IDL?

How do an RMI-IIOP application and an existing CORBA object interoperate?

What is the function of T3 in WebLogic Server?

How can I debug the Java code that I have running in WebLogic Server?

16. FAQs: Server-Side Java (Servlets)

How do I call a servlet with parameters in the URL?

17. FAQs: XML

Which XML parser comes with WebLogic Server 6.0?

Is an XSLT processor bundled in WebLogic Server?

Can I use SAX version 2.0 parsing with WebLogic Server 6.0?

Can I use the getAttribute() and setAttribute() methods of Version 2.2 of the Java Servlet API to parse XML documents?

Does WebLogic Server 6.0 support SOAP?

Can I plug in a version of Apache's Xerces XML parser that is different to the one that is built-in with WebLogic Server 6.0 (Xerces 1.2.0)?

I plugged in a version of Apache Xalan that I downloaded from the Apache Web site, and now I get errors when I try to transform documents. What is the problem?