Passing File objects

Question

It may be that I just don't understand OO principles enough, but I'm having difficulties when I pass a File object to a method. Here's the method that is confusing me.
The method is suppose to change a file's name. It does this just fine. Then I want to change the name inside the File object that points to the file to reflect the new name.
private void foo(File f){
String p = f.getParent();
String n = f.getName();
File tmp = new File(p + "\\" +"Processed_" + n);
boolean b = false;
rename = f.renameTo(tmp);
So then I envoke the method with this
File myFile = new File(pathname);
foo(myFile);
myfile.getname();
Why does myfile.getName return the original name of the file? I pass the myFile by reference to foo(), correct? So when I modify myFile inside foo(), shouldn't those changes persist after exiting foo()?
I've also tried putting this line of code after the rename in foo()
f = new File(p + "\\" +"Processed_" + n);
But when I exit out of foo() this name is not in myFile. myFile still has the original name. The name of the physical file has changed.
Any takers?????
PS when I use f.getName() after the rename inside foo(), the new name is returned.

Answer 1

I looked at the source code for the File class. It appears as if File.renameTo() is indeed renaming the physical file but not updating the name of the file stored in the object; so, when you call getName() after the rename, it returns the original file name.
The Java source method is as follows:
public boolean renameTo(File dest) {
     SecurityManager security = System.getSecurityManager();
     if (security != null) {
     security.checkWrite(path);
     security.checkWrite(dest.path);
     return fs.rename(this, dest);
fs is a FileSystem object.
Basically, this looks like you're the victim of a sin of omission rather than a sin of commission. Your understanding of pointers in Java is not (necessarily) faulty; it's just that it looks like in this case Sun programmers either forgot to add a setName call or they decided it was beyond this scope of the renameTo() method call to do so.