@Override
public abstract boolean isSameFile (FileObject a, FileObject b)

Implementing: javax.tools.JavaFileManager

Compares two file objects and return true if they represent the same canonical file, zip file entry, or entry in any file system based container.

Parameters:
a    a file object
b    a file object

Returns:  true if the given file objects represent the same canonical file, zip file entry or path; false otherwise