Work with JVM properties files

We can use properties files to modify or delete JVM properties.

Determine the changes to make to the JVM configuration.

From the server profile bin directory, run wsadmin -lang jython

Using a properties file, we can modify or delete JVM properties.

Run administrative commands using wsadmin to change a properties file for a JVM, validate the properties, and apply them to the configuration.

Action	Procedure
create	Not applicable
modify	Edit JVM properties in the properties file and then run the applyConfigProperties command. The product ignores null or empty list {} property values, and applies only those values that are not null and non-empty.
delete	Edit the JVM properties file so that it contains only those properties to delete and then run the deleteConfigProperties command. Deleting a property sets the property value to a default value, if it exists. If a default value does not exist for the property, the product removes the property.
create Property	Not applicable
delete Property	Not applicable

Optionally, we can use interactive mode with the commands:

AdminTask.command_name('-interactive')

• Modify an existing properties file.

  1. Obtain a properties file for the JVM to change.

     We can extract a properties file for a JavaVirtualMachine object using the extractConfigProperties command.

  2. Open the properties file in an editor and change the properties as needed.

     Ensure that the environment variables in the properties file match the system.

     An example JavaVirtualMachine properties file follows:

     #
     # Header
     #
     ResourceType=JavaVirtualMachine
     ImplementingResourceType=Server
     ResourceId=Cell=!{cellName}:Node=!{nodeName}:Server=!{serverName}:JavaProcessDef=:JavaVirtualMachine=
     AttributeInfo=jvmEntries
     #
      #
     #Properties
     #
     internalClassAccessMode=ALLOW #ENUM(ALLOW|RESTRICT),default(ALLOW)
     JavaHome="C:\cf50922.30\test/java" #readonly
     debugArgs="-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=7777"
     classpath={}
     initialHeapSize=0 #integer,default(0)
     runHProf=false #boolean,default(false)
     genericJvmArguments=
     hprofArguments=
     osName=null
     bootClasspath={}
     verboseModeJNI=false #boolean,default(false)
     maximumHeapSize=0 #integer,default(0)
     disableJIT=false #boolean,default(false)
     verboseModeGarbageCollection=false #boolean,default(false)
     executableJarFileName=null
     verboseModeClass=false #boolean,default(false)
     debugMode=false #boolean,default(false)
      
     #
     # Header JVM System properties #
     ResourceType=JavaVirtualMachine
     ImplementingResourceType=Server
     ResourceId=Cell=!{cellName}:Node=!{nodeName}:Server=!{serverName}:JavaProcessDef=:JavaVirtualMachine=
     AttributeInfo=systemProperties(name,value)
     #
      #
     #Properties
     #
     com.ibm.security.krb5.Krb5Debug=off
     com.ibm.security.jgss.debug=off
     #
     EnvironmentVariablesSection
     #
     #
     #Environment Variables
     cellName=myCell04
     nodeName=myNode
     serverName=myServer

  3. Run the applyConfigProperties command to create or change a JVM configuration.

     Running the applyConfigProperties command applies the properties file to the configuration. The product ignores null or empty list {} property values, and applies only those values that are not null and non-empty. In this Jython example, the optional -reportFileName parameter produces a report named report.txt:

     AdminTask.applyConfigProperties(['-propertiesFileName myObjectType.props -reportFileName report.txt'])

• If we no longer need a JVM property, we can delete the property, provided the property does not have a default value.

  To delete one or more properties, specify only the properties to be deleted in the properties file and then run the deleteConfigProperties command; for example:

  AdminTask.deleteConfigProperties('[-propertiesFileName myObjectType.props -reportFileName report.txt]')

  If a property has a default value, the property is not deleted but rather is set to the default value.

Results

We can use the properties file to configure and manage the JVM properties.

What to do next

Save the changes to the configuration.

Related tasks

Extracting properties files

Create server, cluster, application, or authorization group objects using properties files and wsadmin scripting

Delete server, cluster, application, or authorization group objects using properties files

PropertiesBasedConfiguration (AdminTask)