Method of loading software with an intermediate object oriented language in a portable device

1. A method of loading software compiled into intermediate object oriented language and comprising several modules for loading into non-volatile memory of a portable digital device equipped with a virtual execution machine, in which said modules are loaded in a form that can be executed by an interpreter of said virtual machine, wherein the loading of at least one of said modules comprises the following steps:

checking for the existence of a data structure associated with said module in the non-volatile memory;

if this data structure does not exist, creating a data structure associated with said module in the non-volatile memory and marking this data structure as not loaded;

resolving links for all internal elements of said module in said data structure and then marking the data structure as loaded;

for every other module referenced in the module being loaded, checking for the existence of a data structure associated with said other module; and

if there is no data structure associated with said other module, creating a data structure associated with said other module in the non-volatile memory and marking this data structure as not loaded.

2. The method according to claim 1 , wherein the step of creating the data structure associated with the module to be loaded comprises the step of storing in this data structure a descriptor of the module to be loaded.

3. The method according to claim 1 ,

wherein the link resolution step comprises:

verifying the existence of a data structure associated with each internal element;

if said data structure does not exist, creating a data structure associated with an internal element in the non-volatile memory;

for each external element mentioned in the module being loaded:

verifying the existence of a data structure associated with this external element;

if said data structure does not exist, creating a data structure associated with an external element in the non-volatile memory.

4. The method according to claim 1 , wherein the loading of said module also comprises, after the link resolution, marking said module as linked if all external modules it mentions are marked as loaded.

5. The method according to claim 4 , wherein:

a check for the existence of a data structure comprises a conformity test between said data structure, if it exists, and its reference in the module being loaded, and the storage of conformity check information; and

deleting the conformity check information of the references when the module is marked as linked.

6. The method according to claim 4 , further comprising the following steps:

initialising the static data of the module marked as linked; and

marking said module as ready for use.

7. The method according to claim 6 , wherein code stored in the digital device and intended to initialise static data is deleted once the module is marked as ready for use.

8. The method according to claim 1 , wherein the modules to be loaded are compiled Java .class files.

9. The method according claim 8 , wherein the data structures are data structures that can be handled by the virtual machine.

10. The method according to claim 8 , wherein the digital device is a chip card with an embedded Java or DotNet virtual machine.

11. The method according to claim 1 , wherein said module loading is carried out for all the program modules.

12. The method according to claim 1 , wherein, following the unavailability of a module, the availability of said module is checked and the module is automatically loaded by the portable device.

13. A loader for a program compiled into an intermediate object oriented language comprising several modules to be loaded in a portable digital device, said loader being stored in the non-volatile memory of the device, said loader accessing modules stored on a source device and executing the following steps in the process of loading the program:

checking for the existence of a data structure associated with a module in the non-volatile memory;

if this data structure does not exist, creating a data structure associated with said module in the non-volatile memory and marking this data structure as not loaded;

resolving links for all internal elements of said module in said data structure and then marking the data structure as loaded;

for every other module referenced in the module being loaded, checking for the existence of a data structure associated with said other module; and

if there is no data structure associated with said other module, creating a data structure associated with said other module in the non-volatile memory and marking this data structure as not loaded.

14. A program loaded in a portable device by the method of claim 1 .

15. A portable digital device comprising non-volatile memory that stores the loader of claim 14 .

16. The device according to claim 15 , wherein the non-volatile memory also stores a program loaded by said loader.

17. The device according to claim 16 , wherein the device is a chip card.

18. The device according to claim 15 , wherein the device is a chip card.