Method and apparatus for storing long-lived objects in a virtual machine

• US 6,681,234 B2
• Filed: 12/12/2000
• Issued: 01/20/2004
• Est. Priority Date: 12/12/2000
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Sokolov, Stepan, Wallman, David
• Primary Examiner(s): Mizrahi, Diane D.
• Application Number:
  US09/736,655
• Publication Number:
  US 20020073404A1
• Time in Patent Office: 1,134 Days
• Field of Search: 707/206, 707/203, 707/103.R, 707/103.Y, 707/103.Z, 712/07, 717/154
• US Class Current: 1/1
• CPC Class Codes: G06F 9/4493 Object persistence
• CPC Class Codes: Y10S 707/99957 Garbage collection

Abstract

One embodiment of the present mechanism provides a system for storing long-lived objects defined within an object-oriented programming system. These long-lived objects are created in a virtual machine used for executing platform-independent code and are ordinarily created during initialization of the virtual machine. The system works by allocating a storage area reserved for long-lived objects that is not subject to garbage collection. After the storage area is allocated, the system receives requests to create an object. The system then determines if the object is a long-lived object by referring to a table of long-lived objects. If the object is a long-lived object, it is created and placed in the reserved storage area.

Claims

1. A method for storing long-lived objects defined within an object-oriented programming system in a virtual machine for executing platform-independent code, wherein long-lived objects are created during initialization of the virtual machine, the method comprising;

allocating a storage area reserved for long-lived objects, wherein the storage area is not subject to garbage collection;

receiving a request to create an object;

determining if the object is identified in a table of long-lived objects;

if the object is identified as a long-lived object, creating the long-lived object, and placing the long-lived object in the storage area;

allowing a garbage collector to reclaim unused storage in the storage area one time just prior to closing the storage area; and

closing the storage area to new objects when initialization of the virtual machine is complete.

2. The method of claim 1, wherein the storage area is an area of a heap used by the virtual machine.

3. The method of claim 2, wherein a remainder of the heap is subject to garbage collection.

4. The method of claim 1, wherein the long-lived object is a persistent string object.

5. The method of claim 4, wherein the persistent string object is a java.lang.String object.

6. The method of claim 1, wherein the virtual machine is a JAVA VIRTUAL MACHINE.

7. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for storing long-lived objects defined within an object-oriented programming system in a virtual machine for executing platform-independent code, wherein long-lived objects are created during initialization of the virtual machine, the method comprising;

allocating a storage area reserved for long-lived objects, wherein the storage area is not subject to garbage collection;

receiving a request to create an object;

determining if the object is identified in a table of long-lived objects;

if the object is identified as a long-lived object, creating the long-lived object, and placing the long-lived object in the storage area;

allowing a garbage collector to reclaim unused storage in the storage area one time just prior to closing the storage area; and

closing the storage area to new objects when initialization of the virtual machine is complete.

8. The computer-readable storage medium of claim 7, wherein the storage area is an area of a heap used by the virtual machine.

9. The computer-readable storage medium of claim 8, wherein a remainder of the heap is subject to garbage collection.

10. The computer-readable storage medium of claim 7, wherein the long-lived object is a persistent string object.

11. The computer-readable storage medium of claim 10, wherein the persistent string object is a java.lang.String object.

12. The computer-readable storage medium of claim 7, wherein the virtual machine is a JAVA VIRTUAL MACHINE.

13. An apparatus that facilitates storing long-lived objects defined within an object-oriented programming system in a virtual machine for executing platform-independent code, wherein long-lived objects are created during initialization of the virtual machine, the apparatus comprising;

an allocating mechanism that is configured to allocate a storage area reserved for long-lived objects, wherein the storage area is not subject to garbage collection;

a receiving mechanism that is configured to receive a request to create an object;

a determining mechanism that is configured to determine if the object is identified in a table of long-lived objects;

a creating mechanism that is configured to create a long-lived object;

a placing mechanism that is configured to place the long-lived object in the storage area;

a garbage collection triggering mechanism that is configured to trigger a garbage collector to reclaim unused storage in the storage area one time just prior to closing the storage area; and

a closing mechanism that is configured to close the storage area to new objects when initialization of the virtual machine is complete.

14. The apparatus of claim 13, wherein the storage area is an area of a heap used by the virtual machine.

15. The apparatus of claim 14, wherein a remainder of the heap is subject to garbage collection.

16. The apparatus of claim 13, herein the long-lived object is a persistent string object.

17. The apparatus of claim 16, wherein the persistent string object is a java.lang.String object.

18. The apparatus of claim 13, wherein the virtual machine is a JAVA VIRTUAL MACHINE.