Migration

This section describes the procedures for migrating to WebLogic JRockit 7.0 SDK. It contains information on the following subjects:

• Running Java^TM Programs with WebLogic JRockit 7.0 JVM
• Replacing the Sun JRE
• Known Problems When Switching Virtual Machines
• Using WebLogic JRockit 7.0 JVM with WebLogic Server

 

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Running Java^TM Programs with WebLogic JRockit 7.0 JVM

You can make WebLogic JRockit 7.0 JVM the default VM for your system. To do this, add the full path of the WebLogic JRockit 7.0 JVM bin directory to your path variable before the path to any other VM.

If you want to run WebLogic JRockit 7.0 JVM without making it the system default you can always use the full path to the java executable when starting a Java program.

 

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Replacing the Sun JRE

As previously stated WebLogic JRockit 7.0 JVM is certified as compatible with J2SE 1.3.1. This means that any Java program that runs using the Sun JRE for J2SE 1.3.1 will run using the corresponding version of WebLogic JRockit 7.0 JVM.

Differences in Command Line Options

The standard command line options available for WebLogic JRockit 7.0 JVM are the same as the Sun JRE for J2SE 1.3.1, with one exception: the option for selecting WebLogic JRockit 7.0 JVM is restricted to -jrockit, which is also the default value.

The non standard options (-X options) for WebLogic JRockit 7.0 JVM are in most cases not the same as the non standard options in the Sun JRE due to differences in design and configurability. Please refer to the BEA WebLogic JRockit 7.0 SDK User Guide for a description of the non-standard options.

 

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Known Problems When Switching Virtual Machines

• On Windows some programs set the system default VM by copying a java.exe file to C:\WINNT\system32. If this happens and this path occurs before the path to WebLogic JRockit 7.0 JVM in your path variable this may cause you to run a different VM than expected.
• Since the command line options (choice of VM and non-standard options) differ from other VMs, remember to change all your start-up scripts accordingly to avoid unexpected errors.

 

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Using WebLogic JRockit 7.0 JVM with WebLogic Server

WebLogic JRockit 7.0 JVM is certified for use with WebLogic Server. For details on exact versions, please see:

• http://www.bea.com/products/weblogic/server/
• http://www.bea.com/products/weblogic/jrockit/

This section describes how easy it is to use these two products together.

Running WebLogic JRockit 7.0 JVM with Thin Threads

Warning: Thin threads is experimental functionality in this version of JRockit, and is not recommended for general use. This feature is subject to change without notice.

The WebLogic JRockit 7.0 JVM high performance thread system (thin threads, -Xthinthreads) and the native I/O system of WebLogic Server are incompatible as they both use asynchronous I/O. To avoid problems the native I/O system of WebLogic Server must therefore be disabled when running WebLogic JRockit 7.0 JVM using thin threads. The native I/O is disabled automatically in WebLogic Server 7.0 SP1 and higher if WebLogic JRockit 7.0 JVM is using thin threads, even if it is turned on in the corresponding WebLogic Server configuration file. In their respective default setups WebLogic JRockit 7.0 JVM does not use thin threads and WebLogic Server uses native I/O.

Switching the Virtual Machine in WebLogic Server

To switch the virtual machine in WebLogic Server, do the following:

1. Open the WL_HOME\server\bin\startWLS.cmd file (Windows) or WL_HOME/server/bin/startWLS.sh (Linux) with any text editor.

2. Edit the line set JAVA_HOME= (JAVA_HOME= in Linux) to point to your WebLogic JRockit 7.0 JVM directory.

3. Remove the text %JAVA_VM% ($JAVA_VM in Linux) in the line near the end of the file.

4. Save and run as usual.

When WebLogic Server is Running as a Service

To switch the virtual machine when WebLogic Server is running as a service, do the following:

1. Stop the service.

2. Start regedit and find the service keys corresponding to your service

(HKEY_LOCAL_MACHINE/SYSTEM/ControlSet001/Services/{ServiceName}).

3. In the Parameters folder, change the value of the key JavaHome from the default VM to your WebLogic JRockit 7.0 JVM directory.

4. Here you can also alter the arguments sent to WebLogic JRockit 7.0 JVM by editing the values of the key CmdLine.

5. Restart the service.