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Technical FAQ: Questions about WebLogic products and other software

- Compiling EJB and RMI classes with Symantec Cafe 3.0

- WebLogic Server runs slowly under VisualAge

- Using Macromedia Generator with WebLogic Server

- Problems loading shared libraries on HP-UX

- Handling exceptions with WebLogic EJB from a Visual Basic client

- Running WebLogic under Windows 95

- Netscape Communicator 4.01 Security Exception

- Why am I getting an access violation in Netscape?

- Problems loading classes using Marimba Castanet tuner version 2.0.

- How do I use the jDriver two-tier drivers with Symantec Cafe?

- Running WebLogic with Microsoft SDK for Java

- Problems running WebLogic under Symantec?

Compiling EJB and RMI classes with Symantec Cafe 3.0

I'm using WebLogic 3.1.8. When I compile my EJB and RMI classes, the Symantec compiler invokes the JavaSoft rmic, which creates Remote interfaces that WebLogic doesn't use. How do I get Symantec to ignore the JavaSoft rmic?

To properly compile EJB or RMI classes you must pass the -normi flag to the sj compiler. Note that this isn't a problem for WebLogic 4.0 or later.

WebLogic Server runs slowly under VisualAge

I am using VisualAge for Java. WebLogic Server seems to run much slower under VisualAge than running in the JavaSoft JVM. What's the problem?

There may be a thread scheduling problem in VisualAge's JVM that is causing this problem. Although we can't debug their JVM, we can suggest several workarounds. If you can live with the slowness during the development phase, you can switch to a different JVM (such as the JDK from JavaSoft) once your application is in production. The only other alternative is to not use the WebLogic Time service while you are developing your application.

Using Macromedia Generator with WebLogic Server

I'm using Macromedia Generator with WebLogic Server. Why do I get a java.lang.VerifyError when WebLogic Server tries to initialize a Macromedia Generator Servlet?

A malformed field name in one of Macromedia's classes is the cause of this problem. There are two methods you can use to suppress verification of class files and avoid receiving this error:

1. Add -noverify to the java command line when you start WebLogic Server. For example,

       $ java -noverify ... [other options] ... weblogic.Server

or

1. Place the Macromedia jar file, flashgen.jar, in your environment (system) classpath. This will force the class to be loaded by the VM, which will also suppress verification of the class file.

Problems loading shared libraries on HP-UX

I just installed WebLogic on my HP-UX system and I am having trouble loading the shared libraries.

You probably need to set the file permissions on your .so or .sl files in the weblogic/lib directory to make them executable. The UNIX command to do this is:

          $ chmod a+x *.sl *.so

For more information see Troubleshooting problems with shared libraries on UNIX.

Handling exceptions with WebLogic EJB from a Visual Basic client

We are using WebLogic COM from a Visual Basic client to access EJBeans which are deployed under WebLogic. If a bean method throws an exception, is it possible to get the exception object, invoke a method on it and then determine if the error generated by Visual Basic is a ValidationException or a RemoteException?

Unfortunately, there are many things you can't do in Visual Basic that you can in Java. When using Visual Basic, you are limited to looking up RMI and EJB objects and calling methods on those objects. In this instance, the best way to handle exceptions is to catch them in the EJBean and return an error message or code to the Visual Basic client.

Running WebLogic under Windows 95

When I try to run a WebLogic client under Windows 95, I receive an error message stating that I am missing the following dll: msvcirt.dll.

This DLL, which is required by the JDK to run the JVM, is installed with Windows NT (and other programs like Microsoft Office and Visual C++), but not with Windows 95. If you are trying to use WebLogic on Windows 95 and have this problem, you will need to get a copy of the DLL and place it in your Windows system directory. Many Windows applications are shipped with this DLL. We suggest that you check your Windows application CDs for a copy.

Netscape Communicator 4.01 Security Exception

I'm using Windows 95 and Netscape Communicator 4.01. Since I installed the latest version of Netscape, I'm getting the following error when I try to access the WebLogic Server running on the same host via HTTP:

    # Security Exception: Couldn't connect to <mybrowser client>
       with origin from <local-classpath-classes>

What's the problem?

The latest version of Netscape's browser doesn't allow an applet to load classes in your local CLASSPATH. All classes must be loaded "over the wire" to satisfy Netscape's security restrictions.

The solution to this problem is to unset CLASSPATH in your general environment, so that you can start the browser in an environment that has no CLASSPATH.

Then, at the prompt in the shell from which you will start WebLogic Server, set your CLASSPATH. See Setting up and starting WebLogic Server for complete instructions on setting your classpath and starting WebLogic Server.

Why am I getting an access violation in Netscape?

I'm using the native jDriver for Oracle and the Netscape Enterprise Server 2.0b4. When I try to execute a JDBC query, I get an HTTPD.EXE access violation. No error message is recorded in my Netscape Enterprise server log. I've verified that the connection to my DBMS is working with utils.dbping, as you instructed in the installation instructions. What's the problem?

You cannot use type-2 native jDriver drivers with the server-side Java in the Enterprise Server because Netscape does not allow third-party Java with native methods. You can use WebLogic JDBC or one of the Type 4 jDriver drivers, since they are Java-only. BEA has type 4 drivers available for Microsoft SQLServer and Informix. You can also use the JConnect type 4 driver, available free from Sybase. This will also solve the problem with Enterprise Server.

Problems loading classes using Marimba Castanet tuner version 2.0.

My application was working fine under Castanet 1.x, but now that I've upgraded to 2.0, I get a "No suitable driver" message when I try to make a database connection. What is going on and what can I do?

Apparently, Castanet loads the java.sql.DriverManager with a different classloader than the one with which the DriverManager attempts to register JDBC Drivers. This means that the recommended JavaSoft paradigm for getting Connection objects does not work under this version of Castanet.

To work around this limitation, replace the lines in your code that look like this:

       Class.forName("weblogic.jdbc.t3.Driver").newInstance();
          Connection conn =
          DriverManager.getConnection("jdbc:weblogic:t3",
                                      t3props);

with this:

        Connection conn =
          new weblogic.jdbc.t3.Driver()
            .connect("jdbc:weblogic:t3",
                     t3props);

While this is not the preferred mechanism for loading classes, it will sidestep the security problems you are experiencing. Marimba is aware of this problem and a bug report has been opened for this case (Bug ID 1801).

How do I use the jDriver two-tier drivers with Symantec Cafe?

I want to use one of your two-tier JDBC drivers with Symantec Cafe. How do I set it up?

The distribution includes a copy of the .dll for the jDriver driver that ends in a trailing _g, for example, weblogicsql14_g.dll. Under Windows NT, the .dll has been linked with javai_g.dll to provide better compatibility with Cafe's debugger facility.

To use the BEA jDriver 2-tier drivers with Cafe, both WebLogic .dlls - the one you installed in java/bin as well as the WebLogic *_g.dll - should be installed in cafe/bin and cafe/java/bin.

Note: Cafe requires CLASSPATH to be set in the configuration file sc.ini, which is found in the /bin directory. Cafe will not read the system environment variable CLASSPATH. See the Cafe documentation for more details.

Running WebLogic with Microsoft SDK for Java

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

You can run WebLogic Server with Microsoft SDK for Java, version 3.2. Here are some things you should know if you use the Microsoft SDK with WebLogic Server:

- Microsoft SDK for Java, version 3.2 is a Java 1.1 implementation.

- When you install WebLogic Server on Windows NT, be sure to use the InstallShield distribution and check the option to install "RMI classes required for Jview." These special classes are not included in the zip file distribution.

- The Microsoft JVM is named Jview.exe. When you install Microsoft SDK for Java, Jview.exe is installed in the bin directory of the Microsoft SDK for Java directory. Note that some other Microsoft products, such as Internet Explorer, install Jview.exe in the WINNT directory. If you have problems with Jview, check your PATH to be sure that the correct version of Jview is executing.

- Instructions for starting WebLogic Server using Microsoft SDK for Java are available in Setting up and starting the WebLogic Server.

  The WebLogic RMI compiler, weblogic.rmic, and the WebLogic EJB compiler, weblogic.ejbs, generate Java code and then call a Java compiler. The default compiler is javac, which is the name of the compiler included in JDKs based on the JavaSoft reference implementation. If you do not have the JavaSoft JDK installed, you must specify the compiler to use on the weblogic.rmic or weblogic.ejbc command line. For example:

        $ jview weblogic.rmic -compiler jvc my.class

        $ jview weblogic.ejbc -compiler jvc mybean.ser

- When starting the server using Microsoft SDK for Java, the rmiForMs.zip file contained in the /lib directory must be included in the classpath. The````````````````````````````````````````````````` startWebLogic.cmd script will automatically do this for you.

- Undeploying and redeploying EJBeans (the "hot deploy" feature) is not supported with WebLogic Server running with Microsoft SDK for Java.

- WebLogic Enterprise Connectivity (IIOP connection pools to WebLogic Enterprise) cannot be used with Microsoft SDK for Java.

- After you install Microsoft SDK for Java, and before you use WebLogic Server, execute clspack -auto, which unloads the Java system classes from the Microsoft JVM to the WINNT\java\classes.zip file.

- Microsoft SDK for Java does not have a jar utility, but the build scripts for the Enterprise JavaBean examples require a jar utility. To build the EJB examples, you must first install a JavaSoft Java Developers Kit (JDK), which you can download from the JavaSoft website. Then, in your development shell, you must do two things:

1. Add the JavaSoft JDK's bin directory to the end of your Windows NT PATH environment variable.

2. Add the JavaSoft JDK's lib/classes.zip file to the end of your CLASSPATH environment variable.

   You can make these changes in the setEnv.cmd script in your WebLogic directory. See Setting your development environment for more on this script.

Problems running WebLogic under Symantec?

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

We have had some reports of difficulties with Symantec's Java, including GPFs when trying to run WebLogic Server. We recommend running the WebLogic Server under the JavaSoft JDK.

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