Chapter 17 Java Virtual Machine and Advanced Settings

This chapter explains how to configure the Java Virtual Machine (JVMJVM^TM) and other advanced settings. It contains the following sections:

• Admin Console Tasks for JVM Settings

• Admin Console Tasks for Advanced Settings

Admin Console Tasks for JVM Settings

• To configure the JVM general settings

• To configure the JVM classpath settings

• To configure the JVM options

• To disable the security manager

• To configure the JVM profiler settings

To configure the JVM general settings

The Java Virtual Machine (JVM) is included in the Java 2 Standard Edition (J2SEJ2SE^TM) software, which is required by the Application Server. Because incorrect JVM settings will prevent the server from running, you should take care when changing these settings.

1. In tree component, select Configurations.

2. Click the JVM Setting node from the target server instance.

3. By default, the General link located below the tabs is already selected.

4. On the JVM General Settings page, you may specify the following:

   1. In the Java Home field, enter the name of the installation directory of the Java 2 Standard Edition (J2SE) software.

      The Application Server relies on the J2SE software. To verify that the J2SE version you specify is supported in this release, refer to the Release Notes. (See the link in the Further Information section.)

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      Note –

      If you enter a nonexistent directory name or the installation directory name of an unsupported version of the J2SE software, then the Application Server will not start.

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   2. In the Javac field, type the command-line options for the Java programming language compiler.

      The Application Server runs the compiler when EJB components are deployed.

   3. To set up debugging with the JPDA (Java Platform Debugger Architecture), you select the Debug Enabled checkbox and specify options in the Debug Options field.

      JPDA is used by application developers. For more information, see the Debugging J2EE Applications chapter of the Application Server Developer’s Guide. (For a link to the guide, see Further Information.)

   4. In the RMI Compile Options field, type the command-line options for the rmic compiler.

      The Application Server runs the rmic compiler when EJB components are deployed.

   5. In the Bytecode Preprocessor field, type a comma separated list of class names.

      Each class must implement the com.sun.appserv.BytecodePreprocessor interface. The classes are called in the order specified.

      Tools such as profilers might require entries in the Bytecode Preprocessor field. Profilers generate information used to analyze server performance. For more information about profiling, see the Debugging J2EE Applications chapter of the Application Server Developer’s Guide.

5. Click Save.

6. Restart the server.

To configure the JVM classpath settings

The classpath is the list of JAR files that the Java runtime environment searches for classes and other resource files.

1. In tree component, select the Application Server node.

2. Click the JVM Settings tab.

3. Select the Path Settings link below the tabs.

4. On the JVM Classpath Settings page, you may specify the following:

   1. In the Environment Classpath checkbox, retain the default selection to ignore the CLASSPATH environment variable.

      The CLASSPATH environment variable is convenient for basic tutorials in programming, but is not recommended for enterprise environments.

   2. To view the Application Server’s classpath, examine the read-only contents of the Server Classpath field.

   3. To insert a JAR file into the beginning of the server’s classpath, enter the full path name of the file in the Classpath Prefix field.

   4. To add a JAR file to the end of the server’s classpath, enter the full path name of the file in the Classpath Suffix field.

      For example, you would specify the JAR file of a database driver. See To integrate a JDBC driver.

   5. In the Native Library Path Prefix and Suffix fields, you may prepend or append entries to the native library path.

      The native library path is a concatenation of the server’s relative path for its native shared libraries, the standard JRE native library path, the shell environment setting (LD_LIBRARY_PATH on UNIX), and any path specified on the JVM Profiler Settings page.

5. Click Save.

6. Restart the server.

To configure the JVM options

On the JVM Options page, you may specify the options of the Java application launcher (java tool) that runs the Application Server. The -D options designate properties that are specific to the Application Server.

1. In tree component, select the Application Server node.

2. Click the JVM Settings tab.

3. Select the JVM Options link below the tabs.

4. On the JVM Options page, to modify an option you edit the Value field.

5. To add an option:

   1. Click Add JVM Option.

   2. In the blank row that appears, type the information in the Value field.

6. To remove an option:

   1. Select the checkbox next to the option.

   2. Click Delete.

7. Click Save.

8. Restart the server.

   For more information about JVM options, see http://java.sun.com/j2se/1.4.2/docs/tooldocs/tools.html and http://java.sun.com/docs/hotspot/VMOptions.html.

To disable the security manager

Disabling the Application Server’s security manager may improve performance for some types of applications. The J2EE authorization and authentication features will still work even if the security manager has been disabled. You may disable the security manager in a development environment, but you should not disable it in a production environment.

1. Go to the JVM Options page of the Admin Console.

   For instructions, see To configure the JVM options.

2. On the JVM Options page, remove this option:

   -Djava.security.policy

3. Click Save.

4. Restart the server.

To configure the JVM profiler settings

A profiler tool generates data that is used to analyze performance and identify potential bottlenecks.

1. In tree component, select the Application Server node.

2. Click the JVM Settings tab.

3. Select the Profiler link below the tabs.

4. The information that you specify on the JVM Profiler Settings page depends on which profiler product you’re using.

   For examples and instructions, see the Debugging J2EE Applications chapter of the Application Server Developer’s Guide. (For a link to the guide, see Further Information.

5. Click Save.

6. Restart the server.

Admin Console Tasks for Advanced Settings

• To set the advanced domain attributes

To set the advanced domain attributes

1. In the tree component, expand the StandAlone instance and select the server instance node.

2. Select the Advanced tab.

3. On the Domain Attributes page, you may do the following:

   1. In the Application Root field, identify the full directory path where the applications will be deployed.

   2. In the Log Root field, specify where the server instance log files are kept.

   3. Typically, you will leave the Locale field blank to use the default locale of the host.

      A locale is an identifier that specifies a particular combination of language and region. For example, the locale for American English is en_US, and for Japanese it is ja_JP. In order to use a non-English locale, the Application Server must be localized, a process that includes translating English into another language.

4. Click Save.

5. Restart the server.