Often in C code (and some other languages as well) I have seen a section in the top-level comments for mod lines. These include the date a modification to the file was made, the user who made the modification, and a brief description of what was changed.
I have not yet seen an equivalent of this in Java. I think this information is useful, especially when trying to track down bugs in code I did not write. Is this because Java code is often under version control, or are there other reasons? Are there any suggestions as to how to include the information in the code file?