Revision as of 17:10, 1 December 2011

Intro

Running garbage collection can have an impact on the response time of a time critical thread.
It is necessary to have memory that is not subject to GC.
Provides two alternatives to traditional Java heap memory:
- Immortal Memory
- Scoped Memory
Both types of area are represented by the abstract javax.realtime.MemoryArea class.
Only javax.realtime.Schedulable objects are allowed to enter into a MemoryArea. If standard Java threads attempt to get in then an IllegalThreadStateException is thrown.
Schedulable objects must explicitly indicate the MemoryArea to allocate objects from, otherwise the standard Java heap will be used.

The memory associated with objects allocated in immortal memory is never GC'ed and never released during the lifetime of the application.
The programmer can reuse the memory by other means. e.g. by maintaining a pool of reusable objects.

@@ Line 6: / Line 6: @@
 ** Immortal Memory
 ** Scoped Memory
 * Both types of area are represented by the abstract javax.realtime.MemoryArea class.
 * Only javax.realtime.Schedulable objects are allowed to enter into a MemoryArea. If standard Java threads attempt to get in then an IllegalThreadStateException is thrown.
+* Schedulable objects '''must explicitly indicate''' the MemoryArea to allocate objects from, otherwise the standard Java heap will be used.
 == Immortal Memory ==
 * The memory associated with objects allocated in immortal memory is '''never GC'ed''' and '''never released''' during the lifetime of the application.
+* The programmer can reuse the memory by other means. e.g. by maintaining a pool of reusable objects.
 [[Category:RealTimeJava]]