A computer-implemented method and a computer program product are provided for converting a first object having a first data format to a second object having a second data format that is different from the first format in that the second data format requires an object header. The method includes adding the object header to the first object. The method further includes returning, as a pointer, an address of the added object header to a user defined function that uses the second object. The first object lacks pointers to other objects, and does not escape.