Correlating class loader objects across execution environments

Patent metadata

Field	Value
Publication number	US-2016154658-A1
Application number	US-201615016789-A
Country	US
Kind code	A1
Filing date	Feb 5, 2016
Priority date	Jun 27, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

Updating a native class pointer in persisted compiled code for use in an execution environment other than the one in which the native class pointer was created. This is done by using an identifier, stored with the persisted compiled code, of the class first loaded by the class loader that also loaded the class to which the native class pointer refers. A table is maintained in the execution environment mapping class identifiers to class loaders, and the stored identifier is used to consult this table to find a candidate class loader from those in the current execution environment that can provide the correct updated pointer.

First claim

1 . A method for use in a first program execution environment, the method comprising:
creating a first map for looking up a class loader by a lookup identifier based, at least in part, on that class loader's first-loaded class; receiving code compiled in a second program execution environment, which code includes: (i) a native class pointer to a target class loaded by a class loader in the second program execution environment, and (ii) an associated lookup identifier based, at least in part, on a first-loaded class of the class loader in the second program execution environment; looking up in the first map, using the associated lookup identifier, a class loader in the first program execution environment; seeking, via a referential identifier of the found class loader, a current native class pointer to the target class; and responsive to finding the current native class pointer, updating the native class pointer in the received code with the current native class pointer.

2 . The method of claim 1 wherein the first map is a hash table.

3 . The method of claim 1 wherein creating the first map includes detecting whether a lookup identifier for looking up a second class loader has already been associated in the first map with a first class loader.

4 . The method of claim 1 wherein the lookup identifier represents a first-loaded class, such that the first map is a map of first-loaded classes to their respective class loaders.

5 - 7 . (canceled)

8 . A computer program product for use in a first program execution environment, the computer program product comprising a computer readable storage medium having stored thereon:
first program instructions programmed to create a first map for looking up a class loader by a lookup identifier based, at least in part, on that class loader's first-loaded class; second program instructions programmed to receive code compiled in a second program execution environment, which code includes: (i) a native class pointer to a target class loaded by a class loader in the second program execution environment, and (ii) an associated lookup identifier based, at least in part, on a first-loaded class of the class loader in the second program execution environment; third program instructions programmed to look up in the first map, using the associated lookup identifier, a class loader in the first program execution environment; fourth program instructions programmed to seek, via a referential identifier of the found class loader, a current native class pointer to the target class; and fifth program instructions programmed to update, responsive to finding the current native class pointer, the native class pointer in the received code with the current native class pointer.

9 . The product of claim 8 wherein the first map is a hash table.

10 . The product of claim 8 wherein creating the first map includes detecting whether a lookup identifier for looking up a second class loader has already been associated in the first map with a first class loader.

11 . The product of claim 8 wherein the lookup identifier represents a first-loaded class, such that the first map is a map of first-loaded classes to their respective class loaders.

12 - 14 . (canceled)

15 . A computer system for use in a first program execution environment, the computer system comprising:
a processor(s) set; and a computer readable storage medium; wherein: the processor set is structured, located, connected and/or programmed to run program instructions stored on the computer readable storage medium; and the program instructions include:
first program instructions programmed to create a first map for looking up a class loader by a lookup identifier based, at least in part, on that class loader's first-loaded class;
second program instructions programmed to receive code compiled in a second program execution environment, which code includes: (i) a native class pointer to a target class loaded by a class loader in the second program execution environment, and (ii) an associated lookup identifier based, at least in part, on a first-loaded class of the class loader in the second program execution environment;
third program instructions programmed to look up in the first map, using the associated lookup identifier, a class loader in the first program execution environment;
fourth program instructions programmed to seek, via a referential identifier of the found class loader, a current native class pointer to the target class; and
fifth program instructions programmed to update, responsive to finding the current native class pointer, the native class pointer in the received code with the current native class pointer.

16 . The system of claim 15 wherein the first map is a hash table.

17 . The system of claim 15 wherein creating the first map includes detecting whether a lookup identifier for looking up a second class loader has already been associated in the first map with a first class loader.

18 . The system of claim 15 wherein the lookup identifier represents a first-loaded class, such that the first map is a map of first-loaded classes to their respective class loaders.

19 - 20 . (canceled)

Assignees

• IBM

Inventors

• Stoodley Mark G

Classifications

• G06F9/44578

  Preparing or optimising for loading · CPC title

• G06F9/44521 Primary

  Dynamic linking or loading; Link editing at or after load time, e.g. Java class loading · CPC title

• G06F8/4441

  Reducing the execution time required by the program code · CPC title