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Technical FAQ: WebLogic Server-related questions

FAQ Index

Problem setting time zone to China Taiwan Time (CTT)

Q I set the time zone in my environmnent to China Taiwan Time (CTT) but the WebLogic Server log reports that the time zone is Central Standard Time (CST). What's wrong?

A This is a bug in the JDK confirmed by JavaSoft. The bug causes the WebLogic Server log to erroneously report that it is using CST instead of CTT although the actual time conversion is correct. There is currently no workaround, but JavaSoft reports that this bug is fixed in JDK 1.2.

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Using SOCKS with WebLogic

Q I am experiencing problems trying to connect from behind a firewall/proxy installation at client sites. Is there any way to configure WebLogic to use a SOCKS proxy?

A You can configure a socket to use SOCKS by setting a Java system property. For details, see How do I make Java work with a proxy server?. Once the property is set, WebLogic's socket connections will use the SOCKS proxy.

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Can I speed up connection requests?

QWe recently installed a WebLogic Server, and found that it seems to take 15-30 seconds to respond to connection requests, even when there is no significant load. How can I speed up connection delays?

A Connection delays are often caused by DNS problems. WebLogic performs a reverse lookup on the hostname from which a new connection is made. If the DNS reverse lookup is not working properly because the connection is coming from some kind of proxy server, it could be responsible for the delay. You might want to work with your system administrator to determine whether DNS and the third-party networking software are working properly. Try writing a simple server program that performs a reverse lookup on any connection made to it. If that lookup is delayed, then you know that the proxy server is the source of the problem.

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Does WebLogic use CORBA? Is it an ORB?

Q What kind of information can you give me about WebLogic's CORBA support? How can CORBA clients communicate with the WebLogic Server via IIOP?

A "CORBA" support means many things to many people. Most frequently, it seems to mean simply IIOP /ORB support and not much on CORBA services. WebLogic supports CORBA in multiple ways.

First, Java clients can tunnel through a CORBA environment to a WebLogic Server. We call this "IIOP tunneling," and it is intended for use with applets coming through an IIOP firewall, such as the IONA Wonderwall product. This is a Java-to-Java model riding over an IIOP communications framework.

A second WebLogic feature is a CORBA gateway provided with the WebLogic Server. It supports pure CORBA clients of any language using either the WebLogic Remote or WebLogic Events services. WebLogic offers an RPC programming model, and it can be used to proxy any of the other WebLogic services for the CORBA client. We provide an IDL to facilitate this integration, and we support VisiBroker in this model. WebLogic Events is supported for CORBA clients, allowing clients to submit and receive asynchronous WebLogic Events.

WebLogic Enterprise Connectivity gives you the ability to create IIOP connection pools to a BEA WebLogic Enterprise, allowing you to execute WebLogic Enterprise CORBA objects from WebLogic Server servlets and Enterprise JavaBeans.

We cannot currently support CORBA connectivity with Java 2 version 1.2, due to class conflicts with Java 2 CORBA support.

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Which WebLogic classes do I need to jar up for my client app?

Q I'm preparing to deploy my WebLogic client application, and I want to separate out those classes that the client will not need. How do I do that?

A It depends on what your client application does. The easy answer is to jar everything in the weblogic/classes directory, as well as the weblogicaux.jar shipped in the weblogic/bin directory.

If your client is a Java application or applet , you may be able to be more selective about which classes you ship to your client. You can use one of the utilities to help you.

The best solution is to use WebLogic ZAC. ZAC (Zero Administration Client) lets you publish your client application for automagic installation on your client machine. ZAC includes features for generating a tiny bootstrapping application that a client can download. It automatically contacts the publishing WebLogic Server to install the client application and then updates it automatically whenever you publish changes.

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Speeding up HTTP tunneling

Q HTTP tunneling is slow! How can I speed it up?

A Unfortunately, there is a significant performance hit when using HTTP tunneling. We hav optimized it somewhat, but because everything is encapsulated in HTTP, it is slower than non-secure communications. We continue to look for ways to optimize our implementation.

Be sure that you really need to use HTTP tunneling. For example, if your firewall can pass IP packets through port 80, you can use the fast t3 protocol on port 80.

If you must use HTTP tunneling to go through a firewall, has a product that performs better than HTTP proxies.

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Using Netscape security certificates with WebLogic

Q I have a Netscape security certificate in ServerKey.der. How do I obtain just the private key?

A Netscape stores the private and public keys together in a key-pair file, which prevents you from separating the public and private keys. In, the property entry [] refers only to the Private Key file. Therefore, you must generate another request for a certificate, not using Netscape utilities. You can use the Certificate Request servlet to generate a request for a new certificate. Using WebLogic SSL shows how to use the servlet.

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Starting the WebLogic Server automatically with a UNIX boot

Q How do I set up the WebLogic Server to execute whenever I reboot the UNIX server?

A You can add a startup script to your UNIX rc scripts to run the WebLogic Server at UNIX boot time. Here is an example from an HP-UX 11 system, running under JDK 1.1. You need to supply the URL for your WebLogic Server and your system password. This file, wlstart, is placed in the /sbin/init.d directory and there is a link to it in the /sbin/rc2.d directory:

export SHLIB_PATH=\
export CLASSPATH=/home/user1/weblogic/classes:\
export ORACLE_HOME=/oracle/8.0.4
export ORACLE_TERM=vt100
export QAT=/home/user1/weblogic
cd $QAT
export PATH
case $1 in
    java -ms64m -mx64m -verbosegc weblogic.Server > \
       /home/user1/weblogic/server.out 2>&1
    java weblogic.Admin URL shutdown system password
    echo "usage: $0 {start|stop}"

You should work with your UNIX system administrator to set up scripts similar to this for your system.

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Servlet performance seem a big sluggish on your NT machine?

Q I'm serving several HTTP servlets over my internal network. Sometimes they are really fast, while at other times the performance seems sluggish. There doesn't seem to be a correlation with actual clients or even network traffic. From the local machine itself, the response time is very fast. Very mysterious. Any ideas?

A As it turns out, we have seen such mysterious behavior ourselves, and we finally tracked it down to something completely unrelated to the network or client usage: response time for a servlet is about 5 times slower when you are running a screen saver on the machine, particularly for the OpenGL screen savers. You might try turning off your screen saver and see if that helps!

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"NoClassDefFound" / "Too many open files" errors on Solaris

Q I'm using WebLogic Server on Solaris. When I try to run my application, I get a "NoClassDefFound" error, although I can see that the class causing the error does exist and is in the right directory. In fact, there are other classes in the same directory that are getting loaded. What's the problem?

Q I'm using WebLogic Server on Solaris. When I try to run my application, I get a "Too many open files" error. What's the problem?

A We have seen this situation when the user account runs out of file descriptors. On Solaris, each user account has a certain limited number of file descriptors. You can find out how many file descriptors you have with the limit command in csh.

You can increase file descriptors if you have enough privileges with the ulimit command in the csh. Otherwise, ask your system administrator to increase the file descriptors available to your processes.

Another solution is to create a .jar file with all of the WebLogic classes, since a .jar file only requires a single file descriptor.

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I can't get the WebLogic Server to start

Q When I try to start the WebLogic Server, I get a "Fatal Error: Cannot open d:\" message. I've installed the WebLogic: classes in a directory in my CLASSPATH. What is the file, and why can't the WebLogic Server find it?

A The file contains configuration information for your WebLogic Server environment. It is shipped in your distribution kit. Unless you use InstallShield under Windows NT/95, you must edit the properties file before you try to start the WebLogic Server, to set host, port, system password, and other WebLogic Server configuration information. For more on the properties file, see Setting WebLogic properties. Once edited, the file should be placed in your weblogic/ directory, along with a subdirectory called "myserver".

When you start the WebLogic Server, it looks first for the properties file in the current directory, and then it checks the path you supply on the command line as weblogic.system.home.

You can cd to the directory containing your file and start the WebLogic Server with the command line example described in Setting up and Starting the WebLogic Server.

Or, if you prefer, you can start the WebLogic Server from any directory using the -D option to set weblogic.system.home. For example, if you have installed the properties file in the directory d:\net\weblogic\, add this to the command line example:

 % java ... -Dweblogic.system.home=d:\net\weblogic\ ...
Startup scripts are provided in the distribution. You can customize these scripts for your system. There are complete instructions on setting up, running, and managing the WebLogic Server in the Administrator Guide, Managing the WebLogic Server.

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Problems with the WebLogic Server running out of memory

Q When I run the WebLogic Server, it runs out of memory very quickly. How do I fix this?

Q I'm using the WebLogic Server for a large number of client connection requests, and occasionally there are memory problems. How can I remedy this?

A Increase the allocation of Java heap memory for the WebLogic Server. (Both the minimum and the maximum should be set to the same size.) Start the 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 the WebLogic Server, which improves performance and allows the WebLogic Server to handle more simultaneous connections. You may increase this value if necessary. See the administrator guide, Tuning the WebLogic Server, for more details.

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Running WebLogic with Microsoft SDK for Java

Q I downloaded your software and tried unsuccessfully to run your WebLogic Server against my installation of Microsoft SDK for Java. Why doesn't it work?

A You can run the WebLogic Server with Microsoft SDK for Java, version 3.2. The corresponding Microsoft SDK For Java version is 5.00.3167.

Instructions for starting the WebLogic Server using JView are available in Setting up and starting the WebLogic Server.

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Problems running WebLogic under Symantec?

Q I'm having some problems running the WebLogic Server under some versions of Symantec's Java. Why is this?

A We have had some reports of difficulties with Symantec's Java, including GPFs when trying to run the WebLogic Server. Please use one of the JDKs we have certified, listed on our Platform support page.

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The WebLogic Console is reporting incorrect hostname and IP address

Q On the Server tab in the WebLogic Console, when I connect to myserver, "loopback" and "" are displayed. How can I get the correct information displayed?

A There is a bug in some VMs that does not correctly read the host name when "localhost" is is the first entry in the hosts table. As a workaround, ask your system administrator to move "localhost" from the top position of the hosts table (/etc/hosts on UNIX) and then restart WebLogic Server.

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What are the exceptions in the log file?

Q I see messages like these in the log file:

(Windows NT) Connection Reset by Peer Connection Reset by Peer
(Solaris) Broken pipe

What causes these messages?

A These messages occur when you are using Servlets, a client initiates an HTTP request, and then performs a series of actions on the browser:

  1. Click Stop or enter equivalent command or keystrokes
  2. Click Refresh or enter equivalent command or keystroks
  3. Send a new HTTP request.

The messages indicate that WebLogic Server has detected and recovered from an interrupted HTTP request.


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Last updated 2/23/2000