8.2 exmemexcludeclass.cfg

Description

exmemexcludeclass.cfg specifies the classes of objects that are not to be moved to the Explicit heap. Even if GC occurs, objects of the classes specified in this configuration file are not moved to the Explicit heap. The objects are moved to the Tenured area at the time of promotion.

The system provides an explicit memory management functionality exclusion configuration file. This configuration file (sysexmemexcludeclass.cfg) provided by the system is used if the functionality that excludes classes from the explicit memory management functionality is enabled. In addition to the classes specified in the configuration file provided by the system, if you want to add classes to be excluded from the explicit memory management functionality, update the configuration file that is stored in the file path below or create a new configuration file. If you create a new configuration file, specify the file path for the -XX:ExplicitMemoryExcludeClassListFile option.

The path of the configuration file that is provided by the system is as follows:

installation_directory_for_JDK/jre/lib/explicitmemory/sysexmemexcludeclass.cfg

You can disable exclusion for the classes specified in this configuration file by using the configuration file that disables exclusions from the explicit memory management functionality. Specifications in the configuration file that disables exclusions from the explicit memory management functionality have priority over those in this configuration file.

The following explains the specification of each configuration file and the scope of the explicit memory management functionality, by using the package "com.sample" as an example. The package "com.sample" includes the following two classes: ClassA and ClassB. The following are specification examples of the configuration files.

Specification example of the explicit memory management functionality exclusion configuration file

com.sample.*

Specification example of the configuration file that disables exclusions from the explicit memory management functionality

com.sample.ClassB

The specification in the explicit memory management functionality exclusion configuration file includes both ClassA and ClassB. However, because the specification in the configuration file that disables exclusions from the explicit memory management functionality has priority, as shown in the figure below, the explicit memory management functionality is applied to ClassB. Only ClassA is excluded from the explicit memory management functionality.

Syntax

For types other than the array type:

fully_qualified_class_name_of_the_specified_class#comment
...
fully_qualified_class_name_of_the_specified_class

For the array type:

"["_repeated_by_the_number_of_dimensions_of_the_array#Lfully_qualified_class_name_of_the_specified_class;

#

For multidimensional arrays, specify [ the same number of times as the number of the dimensions. For example, for a three-dimensional array, specify [[[.

Example for a one-dimensional array of the class aaa.bbb.Myclass:

[Laaa.bbb.Myclass;

The following are the specification rules for this configuration file:

• Specify one class name per line.

• Specify no more than 1,024 characters (including null characters and comments) per line. If 1,025 or more characters are specified in a single line, the line cannot be parsed and a warning message appears. Then, the line is ignored and subsequent lines are loaded.

• You can omit the specification of class names, by specifying package_name.*. Unlike specifying * in the Java language import declaration, if you specify package_name.*, sub-package classes also become targets.

• Enclose the line in one or more consecutive linefeed characters (\n or 0x0A) or carriage return characters (\r or 0x0D).

• Single-byte space characters (0x20) and tab characters (\t or 0x09) will be treated as null characters. Note that all null characters in the configuration file are ignored.

• Prefix each comment with #. All characters from # to end of the line will be treated as the comment.

Storage location

installation_directory_for_JDK/usrconf/exmemexcludeclass.cfg