Why did you use 2 tFileList if you have only 2 files ? The iteration is useless no ?
Personnaly I take the problem more like that :
You can initialise some globalMap in tJava in function of some properties of your file.
In you tFileInput use your variable in the de name file var.
Create 2 contexts var String with default value = INIT
then in your tJava
context.file1 = ((String)globalMap.get("tFileList_1_CURRENT_FILEPATH"));
context.file2 = ((String)globalMap.get("tFileList_1_CURRENT_FILEPATH"));
And in the tFileList, order by "Date of Modif"
Or something like that .
Good luck ,