This section describes the Java HotSpot VM options that can be specified in add.jvm.arg and the precautions to be taken when you specify the options.
The following table describes the Java HotSpot VM options that can be specified in add.jvm.arg. Note that VR is the version of the Application Server in which parameters are introduced or changed.
Table 16-11 Java HotSpot VM options that can be specified when add.jvm.arg is specified
Option name | Contents | Specifiable value | VR |
---|---|---|---|
-Dproperty | Specifies the JavaVM system properties. | The input is not limited. | 05-00 |
-agentlib:libname[=options] | Loads the native agent library libname. | The input is not limited. | 08-00 |
-verbose:information-type | Outputs the information specified in information-type. The following values can be specified in information-type:
| The following strings can be specified:
| 05-00 |
-Xloggc:file | Alike -verbose:gc, the garbage collection event is reported whenever the event occurs; however, that data is recorded in the file. Apart from the information reported when -verbose:gc is specified, the time (unit: seconds) elapsed from the first garbage collection event is added at the beginning of each reported event. | The input is not limited. | 05-00 |
-Xmssize | Sets up the initial size of Java heap. | Specify a natural number using the following units:
| 05-00 |
-Xmxsize | Sets up the maximum size of the Java heap. | Specify a natural number using the following units:
| 05-00 |
-Xmnsize | Sets up the initial value and maximum value of the New area. | Specify a natural number using the following units:
| 05-00 |
-Xsssize | Sets up the maximum size of one stack area. | Specify a natural number using the following units:
| 05-00 |
-Xprof | When this option is specified, a profile of the running program is generated and the profiling data is output in standard output. This option is provided as the utility for developing programs. This option is not intended for use in a real system. | -- | 05-00 |
-Xrunhprof[:suboption=value,...] | Enables the profiling of the CPU, heap, or monitor. Specify a colon ':' behind -Xrunhprof and code '<suboption>=<value>'. You can specify multiple '<suboption>=<value>' separated with comma ','. To acquire the list of sub options and their default values, execute the command java-Xrunhprof:help. | Specify any string. You cannot specify '=' and ',' in <suboption>. Also, you cannot specify ',' in <value>. | 05-00 |
-XrunlibraryName | Specifies the library containing agents such as JVMPI and JVMDI, and the option strings passed at start up. | The input is not limited. | 05-00 |
-Xdebug | When this option is specified, JVMDI support is enabled and started. Hitachi does not recommend JVMDI. Also, this option is not used for debugging in J2SE 5.0. Therefore, this option is not required for debugging in J2SE 5.0. | -- | 05-00 |
-XX:NewRatio=value | Specifies the ratio of Tenured area to New area. If value is 2, the ratio of the New area and the Tenured area is 1:2. If size-of-New-area-being-used ![]() | Specify a natural number value. | 05-00 |
-XX:PermSize=size | Specifies the initial size of Permanent area. | Specify a natural number using the following units:
| 05-00 |
-XX:MaxPermSize=size | Specifies the maximum size for the Permanent area. | Specify a natural number using the following units:
| 05-00 |
-XX:SurvivorRatio=value | Specifies the ratio of New::Eden area to the From space and To space of New::Survivor area. If 8 is set in value, the ratio of the New::Eden area, From space and To space is 8:1:1. | Specify a natural number value. | 05-00 |
-XX:[+|-]PrintTenuringDistribution |
| The following characters can be specified:
| 05-00 |
-XX:TargetSurvivorRatio=value | Specifies the target value (0 to 100 (unit: %)) for the ratio occupied by the Java objects in New::Survivor area after garbage collection is executed. | Specify a natural number value. | 05-00 |
-XX:MaxTenuringThreshold=value | Specifies the threshold value for the number of times a Java object is replaced in the From space and To space when copy garbage collection is executed. The Java objects to be replaced after the specified count is exceeded are moved to Tenured area. The valid range of this option is from 0 to the default value. If a value outside the range is specified, the function for moving to the Tenured area is disabled if exceeds the threshold value. | Specify a natural number value. | 05-00 |
-Xrunhndlwrap | Specifies whether to continue an execution of JavaVM, if you log off the Windows in an environment earlier than the JDK version 5. If -XX:+EagerXrunInit is specified, specification of this option is invalid or -agentlib:hndlwrap2. If -agentlib:hndlwrap2 is set, do not set this option. This option cannot be used concurrently with another JVMTI version program. If you log off Windows when a Java program using this option is being executed at the command prompt, an error popup stating 'Program is not responding' appears and you cannot log off. | -- | 05-01 |
-agentlib:hndlwrap2 | Specifies whether to continue an execution of JavaVM, if you log off the Windows is in an environment with JDK version 6. If -Xrunhndlwrap is set, do not set this option. This option cannot be used concurrently with other JVMTI version programs. If you log off Windows when a Java program using this option is being executed at the command prompt, an error popup stating 'Program is not responding' appears and you cannot log off. | -- | 08-50 |
-XX:[+|-]UseSerialGC#1 |
| The following characters can be specified:
| 08-70 |
-XX:[+|-]UseParNewGC#1 |
| The following characters can be specified:
| 08-70#2 |
-XX:ParallelGCThreads | Specifies the number of threads that will execute copy garbage collection in parallel. This option is enabled when -XX:+UseParNewGC is specified. Also, we recommend that you use the default value for this option. If you want to change the value, calculate the optimum value based on the value measured by actually operating JavaVM, and then change the value. When JavaVM starts, the number of garbage collection threads specified in this option are created and the processing is executed. The default values used when this option is omitted are as follows:
If you specify 0 in this option, a serial copy garbage collection is executed. Note the following when you specify a value:
| Specify a natural number value. | 08-70 |
Table 16-12 References for the default values of the Java HotSpot VM options for each server and application
Server and application used | Reference |
---|---|
J2EE server | 2.3 usrconf.cfg (Option definition file for J2EE servers) |
Batch server | 3.2 usrconf.cfg (Option definition file for batch servers) |
Web Container Server (Compatibility function) | 3.11.2 usrconf.cfg (Option definition file for Web Container Server) in the manual Cosminexus Application Server Function Guide - Compatibility. |
Java applications started with the cjclstartap command | 14.2 usrconf.cfg (Option definition file for Java applications) |
Other Java applications | 16.4 Default values of the Java HotSpot VM options that can be specified in Cosminexus |