The objects that you want to place in the Explicit heap (Explicit memory block) must satisfy the following prerequisites:

• The object must be a long-life object, which is the cause of increase in the Tenured area memory size
  A certain amount of overhead is required for placing and releasing objects for Explicit memory blocks. Therefore, reduce the placing and releasing of objects in Explicit memory blocks as much as possible.
  When you are not using the Explicit Memory Management functionality and, if you place a short-life object, which was targeted for recovery in the copy garbage collection, it does not meet the objective of inhibiting a full garbage collection and hence causes overhead. In Explicit memory blocks, make sure to place long-life objects that are not targeted for recovery in the copy garbage collection.
  For details on how to identify long-life objects that cause an increase in the Tenured area memory size, see 9.8 Functionality of statistics of unnecessary objects in Tenured area in the uCosminexus Application Server Maintenance and Migration Guide.
  
• Survival period should be known (only when you use the Explicit Memory Management functionality API)
  When you use Explicit Management Heap by using the Explicit Memory Management functionality API, used objects are not automatically recovered because the Explicit memory blocks are not targeted for garbage collection.
  The objects placed in Explicit memory blocks need to be explicitly released by an application. However, if the survival period of the objects is not known, the objects cannot be explicitly released. Therefore, make sure to place only those objects, the survival period of which is known.
  

From among the long-life objects, the Explicit Memory Management functionality prevents objects that are destroyed after a fixed period and recovered in the full garbage collection, from rising to the Tenured area. Therefore, you need not apply the functionality to objects that are not recovered even in a full garbage collection, such as the objects used until the application stops.

The objects that are effective when placed in the Explicit heap are as follows:

• Objects that are generated and destroyed in a fixed life cycle.
• Used objects, which are not properly recovered after destruction because life cycle period is longer than the period of rising of objects due to the copy garbage collection.

You can prevent unnecessary objects from remaining in the Tenured area by placing such objects in the Explicit heap, and thus inhibit the full garbage collection.