File.renameTo() fails on Linux Ubuntu within the same file system

[suraj sahitya]

I am aware that I can use Files.move to rename a file in Java 7/8. But this question is specifically with java.io.File.renameTo() with Java 8...

As you can see from the code both the files are in the same mount point as well as same file system. The value status returns false.

public static final void main(String[] args) {
        File f = null;
        File f1 = null;
        boolean status = false;

        try {
            // create new File objects
            f = new File("/home/suraj/a.txt");
            f1 = new File("/home/suraj/renamed.txt");

            status= f.renameTo(f1);

            System.out.println("The value of status is " + status);

        } catch (Exception e) {
            // if any error occurs
            e.printStackTrace();
        }
    }

Any thoughts on why this would happen ?

[Knute Snortum]

Can you post the stack trace?

[Campbell Ritchie]

And what happens? Does it compile? Do you get an Exception? Do those files actually exist on the file system?

[suraj sahitya]

Knute Snortum wrote:Can you post the stack trace?

There is no stack trace. It prints false. There is no exception. Yes it does compile.

[Knute Snortum]

A status of zero means no error in Linux.

Edit: never mind, the renameTo() function changes the OS status to boolean.

[suraj sahitya]

Campbell Ritchie wrote:And what happens? Does it compile? Do you get an Exception? Do those files actually exist on the file system?

a.txt does exist on the file system.


When I add this line of code

FileOutputStream fos = new FileOutputStream(f);

it does work.

[suraj sahitya]

Knute Snortum wrote:A status of zero means no error in Linux.

But the file did not get renamed.

[Knute Snortum]

Yeah, I was mistaken about what renameTo() returns. I thought it was the OS status but it's not.

[suraj sahitya]

Knute Snortum wrote:Yeah, I was mistaken about what renameTo() returns. I thought it was the OS status but it's not.

So what are my options ? Use Files.move() and let this silently die. Or investigate this further ?

[Knute Snortum]

What happens if you try the same rename from the Linux command prompt?

[Knute Snortum]

Does "/home/suraj/renamed.txt" already exist?

[suraj sahitya]

Knute Snortum wrote:What happens if you try the same rename from the Linux command prompt?

You mean run /usr/bin/rename ?

[suraj sahitya]

Knute Snortum wrote:Does "/home/suraj/renamed.txt" already exist?

No renamed.txt does not exist.

[Knute Snortum]

Right. I believe it fails if the file to rename to already exists.

[devendra K Kumar]

Hi ,

I ran the code in my local system its working fine , but when i modify the security credential on file then i am also getting the false value ,so please check the read/write access to file .

[suraj sahitya]

devendra K Kumar wrote:Hi ,

I ran the code in my local system its working fine , but when i modify the security credential on file then i am also getting the false value ,so please check the read/write access to file .

I did a chmod 777 on a.txt and I still get a false :-)

[Knute Snortum]

Did you try:

$ rename "/home/suraj/a.txt" "/home/suraj/renamed.txt"

[devendra K Kumar]

suraj sahitya wrote:

devendra K Kumar wrote:Hi ,

I ran the code in my local system its working fine , but when i modify the security credential on file then i am also getting the false value ,so please check the read/write access to file .

I did a chmod 777 on a.txt and I still get a false :-)

After doing chmod 777 , check the access parameter .

ll a.txt

[suraj sahitya]

Knute Snortum wrote:Did you try:

$ rename "/home/suraj/a.txt" "/home/suraj/renamed.txt"

I did and this is what I get -

Unknown regexp modifier "/w" at (eval 1) line 1, at end of line
Unknown regexp modifier "/n" at (eval 1) line 1, at end of line
Bareword "suraj" not allowed while "strict subs" in use at (eval 1) line
Bareword "a" not allowed while "strict subs" in use at (eval 1) line 1.
Bareword "txt" not allowed while "strict subs" in use at (eval 1) line 1.

[suraj sahitya]

devendra K Kumar wrote:

suraj sahitya wrote:

devendra K Kumar wrote:Hi ,

I ran the code in my local system its working fine , but when i modify the security credential on file then i am also getting the false value ,so please check the read/write access to file .

I did a chmod 777 on a.txt and I still get a false :-)

After doing chmod 777 , check the access parameter .

ll a.txt

It is r-wxrwxrwx. But still false ;-)

[Knute Snortum]

That looks like Perl.

[suraj sahitya]

Knute Snortum wrote:That looks like Perl.

So Knute what is the solution ? Is LINUX rename on Ubuntu the problem ?

[Knute Snortum]

My Linux is rusty. Try:

$ mv "/home/suraj/a.txt" "/home/suraj/renamed.txt"

[suraj sahitya]

Knute Snortum wrote:My Linux is rusty. Try:

$ mv "/home/suraj/a.txt" "/home/suraj/renamed.txt"

That works without an issue.

So use Files.move from Java 7/8 ? ;-)

[devendra K Kumar]

suraj sahitya wrote:

devendra K Kumar wrote:

suraj sahitya wrote:

devendra K Kumar wrote:Hi ,

I ran the code in my local system its working fine , but when i modify the security credential on file then i am also getting the false value ,so please check the read/write access to file .

I did a chmod 777 on a.txt and I still get a false :-)

After doing chmod 777 , check the access parameter .

ll a.txt

It is r-wxrwxrwx. But still false ;-)

try chmod 755 or 744

[suraj sahitya]

Knute Snortum wrote:My Linux is rusty. Try:

$ mv "/home/suraj/a.txt" "/home/suraj/renamed.txt"

If you look at the code of UnixFileSystem.java from java.io this is how it looks like. You think this code calls my rename on Linux Ubuntu and fails ?

 public boolean rename(File f1, File f2) {
        // Keep canonicalization caches in sync after file deletion
        // and renaming operations. Could be more clever than this
        // (i.e., only remove/update affected entries) but probably
        // not worth it since these entries expire after 30 seconds
        // anyway.
        cache.clear();
        javaHomePrefixCache.clear();
        return rename0(f1, f2);
    }
    private native boolean rename0(File f1, File f2);

[suraj sahitya]

devendra K Kumar wrote:

suraj sahitya wrote:

devendra K Kumar wrote:

suraj sahitya wrote:

devendra K Kumar wrote:Hi ,

I ran the code in my local system its working fine , but when i modify the security credential on file then i am also getting the false value ,so please check the read/write access to file .

I did a chmod 777 on a.txt and I still get a false :-)

After doing chmod 777 , check the access parameter .

ll a.txt

It is r-wxrwxrwx. But still false ;-)

try chmod 755 or 744

Tried both and both fail :-)

[Knute Snortum]

suraj sahitya wrote:So use Files.move from Java 7/8 ? ;-)

Yeah, I would try that.

[Campbell Ritchie]

Too difficult a question for this forum. Moving discussion.

And maybe duplicating in the Linux forum. Beware of the mod there

[Knute Snortum]

I just wrote this:

import java.io.File;

public class MoveMe {

  public static void main(String... args) {
    File a = "/home/knute/a.txt";
    File b = "/home/knute/rename.txt";
    boolean status = a.renameTo(b);
    System.out.println(status);
  }

}

I executed this in Ubuntu, Java 8. No problems.

[suraj sahitya]

Knute Snortum wrote:I just wrote this:

import java.io.File;

public class MoveMe {

  public static void main(String... args) {
    File a = "/home/knute/a.txt";
    File b = "/home/knute/rename.txt";
    boolean status = a.renameTo(b);
    System.out.println(status);
  }

}

I executed this in Ubuntu, Java 8. No problems.

Yea but it does not work in mine. That is the problem :-) So unless we can debug the native implementation of rename in jdk source code I am going to use Files.move :-). Works every single time.