9.2 Overview of the product JavaVM functionality
The process of the J2EE server or the batch server running in the Application Server is executed on the JavaVM. The functionality provided by the product JavaVM is as follows:
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Explicit Memory Management functionality
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Class-wise statistical functionality
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Instance statistical functionality
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STATIC member statistical functionality
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Reference-related information output functionality
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Pre-statistical GC selection functionality
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Unused objects statistical functionality in the Tenured area
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Base object list output functionality for Tenured augmentation factors
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Class-wise statistical information analysis functionality#
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Tenuring distribution output functionality of the Survivor area
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hndlwrap functionality
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Functionality to set the upper limit of allocation size of C heap during JIT compilation
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Functionality to set the upper limit of the number of threads
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If using the class-wise statistical information analysis functionality, you can output the class-wise statistical information to the extended thread dump file in the CSV format.
- Tip
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When you execute the unused objects statistical functionality in the Tenured of the class-wise statistical functionality, the following functionality are disabled:
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Instance statistical functionality
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STATIC member statistical functionality
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Pre-statistical GC selection functionality
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In the product JavaVM, the output contents of the log are expanded so that the output contents can be used for the cause analysis of the error occurrence and for checking the system state. This log is output to the Hitachi JavaVM log file, and therefore, you can acquire many troubleshoot information than the standard JavaVM. You can improve the system availability by implementing an appropriate tuning using this log (extended verbose information). For details about the Hitachi JavaVM log files, see 5.7 JavaVM log (JavaVM log file). For details about the tuning of the Java VM, see 7. JavaVM Memory Tuning in the uCosminexus Application Server System Design Guide.
Hereafter, the following section describes each functionality of the product JavaVM. For details about the Explicit Memory Management functionality, see 7. Suppression of Full GC by Using the Explicit Memory Management Functionality in the uCosminexus Application Server Expansion Guide.