Release processing is executed when you specify -ehgc option and execute javagc command.

Note

With release processing of Explicit memory blocks by using the javagc command, a full garbage collection is executed. Hence, it is not appropriate for the processing related to running applications. We recommend that you execute release processing when the application is not running, such as at the time of undeploying and at night time.

When you execute the javagc command, JavaVM executes a full garbage collection and outputs the EMJavaGC command as the cause of the garbage collection in extended the verbosegc information. After that, the following Explicit memory blocks are released:

• Explicit memory blocks that are reserved by explicit release reservation, when automatic release functionality of the Explicit Memory Management functionality is enabled
• Explicit memory blocks generated by the explicit management heap automatic placement configuration file or JavaVM
• Explicit memory blocks that were not released in the previous release processing

For details on the causes of a garbage collection, see -XX:[+|-]HitachiVerboseGCPrintCause (garbage collection cause content output option) in the uCosminexus Application Server Definition Reference Guide.

The release processing is not executed in the following cases:

• When you try to release Explicit memory blocks exceeding the maximum limit
  This refers to the case when the number of existing Explicit memory blocks is 1,048,575.
  
• When the Explicit Memory Management functionality is OFF
  This refers to the case when -XX:-HitachiUseExplicitMemory option is specified.
  

In this case, although the constructor is successfully executed, memory blocks are handled as invalid Explicit memory blocks (ExplicitMemory instances).