This topic applies only on the IBM i operating system.

Enabling servers to use the IBM Technology for Java Virtual Machine

The Web server plug-ins, an application client, an application server, or individual profiles within an application server might be enabled to use the classic Java virtual machine (JVM) that is provided with IBM i Version 6.1 and lower. When upgrading to IBM i Version 7.1 or higher, use the enablejvm command to enable your Web server plug-ins, application clients and application servers to use the 32-bit (std32) or 64-bit (std64) version of the IBM Technology for Java Virtual Machine. IBM i Version 6.1 is the last version of IBM i that supports the classic JVM.

Before you begin

  • Read the enablejvm command topic. You must issue various enablejvm commands to complete this task.
  • Check the settings of the was.use.j9 and was.j9.version properties in either the plugins_root/properties/product.properties file, the app_client_root/properties/product.properties file, or the app_server_root/properties/product.properties file to determine the JVM that your Web server plug-ins, application client, or application server is enabled to use:
    • If the was.use.j9 property is set to false, then your Web server plug-ins, application client, or application server is enabled to use the classic JVM.
    • If the was.use.j9 property is set to true, and the was.j9.version property is set to 32-bit, then your Web server plug-ins, application client, or application server is enabled to use the 32-bit (std32) version of the IBM® Technology for Java Virtual Machine.
    • If the was.use.j9 property is set to true, and the was.j9.version property is set to 64bit, then your Web server plug-ins, application client, or application server is enabled to use the 64-bit (std64) version of the IBM Technology for Java Virtual Machine.

    If your application server is configured to use the classic JVM, check the settings for the was.use.j9 and was.j9.version properties in the profile_root/properties/.instance.properties file for each of the profiles within your application server to determine if any of these profiles are enabled to use the 64-bit version of the IBM Technology for Java Virtual Machine. If the was.use.j9 property is set to true, and the was.j9.version property is set to 64bit, then the profile is enabled to use the 64-bit version of the IBM Technology for Java Virtual Machine. Note the names of any profiles that are enabled to use the 64-bit version of the IBM Technology for Java Virtual Machine so that you can re-enable these profiles to use the 64-bit version after you enable the application server to use the 32-bit version of this JVM.

    If your application server is already configured to use either version of the IBM Technology for Java Virtual Machine, check the settings for the was.use.j9 and was.j9.version properties in the profile_root/properties/.instance.properties file for each of the profiles running on your application server to determine if any of these profiles are enabled to use the classic JVM. If the was.use.j9 property is set to false, then the profile is enabled to use the classic JVM. Note the names of any profiles that are enabled to use the classic JVM so that you can enable these profiles to use either the 32-bit or 64-bit version of the IBM Technology for Java Virtual Machine.

About this task

When upgrading to IBM i Version 7.1 or higher:

  • If your Web server plug-ins, or application client is enabled to use the classic JVM, enable your Web server plug-ins, or application client to use the 32-bit version of the IBM Technology for Java Virtual Machine.
  • If your application server is enabled to use the classic JVM, enable your application server to use the 32-bit version of the IBM Technology for Java Virtual Machine.
  • If your application server is enabled to use either the 32-bit or 64-bit version of the IBM Technology for Java Virtual Machine, and some of the profiles within your application server are enabled to use the classic JVM, enable all profiles that currently use the classic JVM to use either the 32-bit or 64-bit version of the IBM Technology for Java Virtual Machine.

Procedure

Results

All of the servers on your system are enabled to use either the 32-bit or 64-bit version of the IBM Technology for Java Virtual Machine instead of the classic JVM.

What to do next

Consider tuning the JVM for all application server profiles that you switched from the classic JVM to either the 32-bit or 64-bit version of the IBM Technology for Java Virtual Machine. The default settings for the IBM Technology for Java Virtual Machine might not be appropriate for your application server.

For example, the default initial Java heap size and maximum Java heap size are different for IBM Technology for Java Virtual Machine than for the classic JVM. When application server profiles are enabled for either the 32-bit or 64-bit version of the IBM Technology for Java Virtual Machine, the default initial and maximum heap sizes are 50 MB and 256 MB, respectively. For the classic JVM, the default initial and maximum heap sizes are 96 MB and 0 MB, where 0 indicates that there is no maximum value.




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Last updatedLast updated: Feb 5, 2014 9:49:51 PM CST
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