Managing persistent and temporary data objects in a portable data carrier

A portable data carrier having a processor for executing a program and a first and a second memory region for storage of objects generated in program execution, wherein write operations to the second memory region are performed faster than write operations to the first memory region, and wherein the second memory region is organized as a heap memory with an occupied portion and a free portion, and wherein a fill level indicator indicates a boundary between the occupied portion and the free portion of the second memory region, and wherein the memory contains instructions which cause the processor to carry out a process for memory management in the execution of the program, comprising:

• creating an object at least in part in the second memory region, wherein the object is created during execution of a certain method of the program, wherein the certain method is distinct from a “select” method and distinct from a “deselect” method, which are called when changing between a plurality of programs of the portable data carrier, and wherein the program comprises the certain method and the “select” and “deselect” methods;
• monitoring, during further program execution, as to whether a persistently stored reference to the object is generated;
• transferring the object to the first memory region if, in the course of further program execution, said monitoring determines that a persistently stored reference to the object is generated;
• and
• on termination of said certain method, during execution of which the object was created, executing operations comprising:
• checking whether or not the certain method returns a reference to an object located in a certain portion of the second memory region, wherein the certain portion has been newly occupied by the certain method since the certain method was called;
• and
• if said checking indicates that the certain method does not return a reference to an object located in the certain portion of the second memory region, then resetting the fill-level indicator, which indicates the occupation of the second memory region, to the level current when the certain method was called, thus freeing up any memory space in the second memory region up to the level current when the certain method was called.