Java.io.File.renameTo

Is there any limitation on renameTo(file) method. It fails when I try to rename a file from root user to a different file which belongs
to a different user. I'm running the code as root. Root should have permission to write anywhere.
Also, I'm trying to rename the file within the same physical device.

I have gone thru javadoc, but it does not provide the necessary answer. I don't get any error message or exception.
I'm using RHEL 5.2 and jdk 1.5.

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Java.io.File renameTo does not work on Solaris

Hi Experts,
I have a code-piece which tries to move files from one directory to another on the SAME FILE SYSTEM using java.io.File.renameTo method.
It works fine when there less no. of files in the source directory. But the renameTo does not work as expected when there are very huge no. of files(~40K) present in the source directory.
I am aware that there is a known issue when one tries to use this method to move files across file systems OR if the file exists at the destination directory.
But in my case the file system is the same and the there is no such file in the destination directory.
I suspect some inode related issues. But not sure what it is exactly.
Is there any limitations of renameTo?
Please help.

OK, we all now understand you have a problem in doing this, but without the specifics of the problem that you are experiencing, then it is fairly difficult to give you anything other than a guess. If you would like some specific and relevent answers, please supply specifics about how exactly the operation differs from your expected results. You should also post example code as it is almost always asked for eventually.

File.renameTo() bugg? Leaves the file open

I came across the strangest behaviour of File.renameTo() for the following steps:
1. Rename a file - successful
2. Rename the same file again - will fail. Also delete will fail.
-------- some code ----------
File file=new File("F1");//nonexistent file
//write some to the file - just to make the file to be created
RandomAccessFile rFile=new RandomAccessFile(file,"rw");
rFile.writeBytes("Hello");
rFile.close();
//A successful rename
boolean renamed=file.renameTo(new File("F2"));
System.out.println("renamed="+renamed);
//This is commented code for now
//rFile=new RandomAccessFile(file,"rw");
//rFile.close();
//This rename fails!
renamed=file.renameTo(new File("F3"));
System.out.println("renamed again="+renamed);
As it seems File.renameTo() sets the file to open, since neither renameTo or delete will work after a renameTo.
BUT, if I uncomment the commented code, it will work again! I just open a dummy RandomAccessFile (FileInputStream would work as well I guess) and then close it, and somehow the file is set to closed again, and the second renameTo() will work.
Is this a bugg in File.renameTo()? I run on windows XP and have java 1.4.1_02-b06. I couldn't find any comment about this in the Bug Database.
Gil

Aha! so the reason why the opening of the dummy RandomAccessFile did it in my previous code, was becase it created the old File "F1" again that could be renamed again. So the correct code should instead be:
-------- some code ----------
File file=new File("F1");//nonexistent file
//write some to the file - just to make the file to be created
RandomAccessFile rFile=new RandomAccessFile(file,"rw");
rFile.writeBytes("Hello");
rFile.close();
//A successful rename
File file2=new File("F2");
boolean renamed=file.renameTo(file2);
System.out.println("renamed="+renamed);
//Now this rename also succeeds!
renamed=file2.renameTo(new File("F3"));//do rename on file2!
System.out.println("renamed again="+renamed);
Gil

File.renameTo method issue

I have a Java program which processes upto 10000 text files a day. The average size of these files are 1KB to 2KB and the java program parses the contents of the text file, validates and loads them into a database table.
The program outline is as follows
File[] filesToProcess = sourceFolder.listFiles();
int fileCount = filesToProcess.length;
for (int i=0;i<fileCount;i++) {
File currentFile = filesToProcess;
MsgParser fileParser = new MsgParser(currentFile);
if ( fileParser.isMessageValid()) {
boolean uploadSuccess = fileParser.uploadToDB();
if (uploadSuccess) {
if (currentFile.renameTo(parseSuccessArchiveFile))
logger.info("File successfully moved to archive folder);
else
logger.info("File cannot be moved to archive folder);
} else {
if (currentFile.renameTo(parseFailureArchiveFile)
logger.info("Parser failed file moved to archive folder);
else
logger.info("Parser failed file cannot be moved to archive folder);
The above program outline works well. However the renameTo method is not renaming the parsed files successfully on all occasions. There is no performance issue involved here as the files keep streaming in throughout the day and the program is able to handle the parsing of the file(s) in a fraction of second.
The issue for me is that I keep picking the files to parse from the source folder at regular intervals ( after a full iteration of the files list, wait for 10 seconds before calling for a new set of files ) and cannot afford to have a failure in moving the file to the archive folder as otherwise, I end up parsing the same file multiple number of times, which I want to avoid.
Can anyone shed some light on the behavior of File.renameTo and how to make it work successfully?
Sundar

I am making the code more readable for you all and corrected some typo errors...
File[] filesToProcess = sourceFolder.listFiles();
int fileCount = filesToProcess.length;
for (int i=0;i<fileCount;i++) {
      File currentFile = filesToProcess;
      MsgParser fileParser = new MsgParser(currentFile);
      boolean uploadSuccess = false;
      if ( fileParser.isMessageValid())
           uploadSuccess = fileParser.uploadToDB();
      if (uploadSuccess) {
            if (currentFile.renameTo(parseSuccessArchiveFile))
                  logger.info("File successfully moved to archive folder);
            else
                  logger.info("File cannot be moved to archive folder);
      } else {
            if (currentFile.renameTo(parseFailureArchiveFile)
                  logger.info("Parser failed file moved to archive folder);
            else
                  logger.
                  info("Parser failed file cannot be moved to archive folder);
}

File.renameTo(..) does not work with NFS?

I have some code the essentially does this:
1. Create Destination Directories
file.mkdirs(..);
2. For each file..'rename to destination'
for (..)
file.renameTo(..);
* Where the rename To is 'moving' the file to the dest directory.
This code works fine on LocalDrive to LocalDrive.
But when I goes to the NFS...
The Directories get created on the NFS.
But the files never make it there..no exception is thrown...
Has Anyone encountered such behavior before?
The system obviosly has write permissions since the directories do get created...

ok...something that has been bugging me..
We all know that Java IO is dog slow (perhaps now with 1.4 it is better with non blocking io)..but..here's my gripes..
for Java API calls where a native equivalent exists on the OS, then native equivalent should be invoked (as it is more then likey going to be faster). In other words shouldnt renameTo call mv on unix.
now java has no copy method..so..some time ago..I implemented a 'native' copy..simply system.exec("cp ") etc..(much quick the copying the streams)
This works..but after finding out the system.exec FORKS the entire VM, we can no longer use this, as memory requirements are strict.
It seams to me that sun has messed up here...
or am I missing something?
thoughts?
Dan

Java.io.File not found in JDK 1.4

why the java.io.file is deprecated.
Frans

[fthamura],
why the java.io.file is deprecated.Probably because in J2SE 1.4, the New I/O package java.nio package provides scalable I/O operations for files. Through the File channels, a programmer will be able to provide memory-mapped buffers, improved file locking mechanism and faster I/O transfers with the new API package.
FransHTH.
Allen Lai
Developer Technical Support
SUN Microsystems
http://www.sun.com/developers/support/

Getting all the members (variables, methods AND method bodies) of a java source file

For a project I want to programmatically get access to the members of java source file (member variables, methods etc) as well as to the source code of those members. My question is what is the best method for this? So far I have found the following methods:
Use AST's provided by the Java Source API and Java Tree API, as discussed in the following posts:
http://today.java.net/pub/a/today/2008/04/10/source-code-analysis-using-java-6-compiler-apis.html
http://weblogs.java.net/blog/timboudreau/archive/2008/02/see_java_code_t.html
http://netbeans.dzone.com/announcements/new-class-visualization-module
This has the disadvantage that the classes actually have to be compilable. When I look at the Netbeans Navigator view however, it provides me with a nicely formatted UI list, regardless of the "compilable" state of the class.
Thus I started looking at how to do this... The answer appears to be through the use of tools such as JavaCC: https://javacc.dev.java.net/
ANTLR: http://www.antlr.org/
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Another route seems to be through tools such as
BeautyJ: http://beautyj.berlios.de/
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I hope someone can shed a light on the best way to go about what I want to achieve. Somebody already doing this?
(I crossposted on the Netbeans forums too, hope this is OK...)

I'm currently developing a LaTeX editor(MDI) and I do the same thing, but I don't know what exactly do you need.

How to read the java class file to convert it in java.

hello all,
i m developing the java application which generated the java code from the java 'class file' .
Can anybody please help me, Is any java support for reading the class file? or how to know the class file format?
I know the application javad, jad, javap which is doing the same thing.
thanks for reply,
- Jayd

do you mean decompiling? there are tons of java decompilers available out there, what exactly are you trying to do here?

How to convert a .jsp to a .java/.class file for use in peoplesoft

Hi java/jsp experts,
I want to convert a .jsp to a .java/.class file. is there a tool available, please let me know if you have any pointers....
or can i do it manually:
these are a few lines that the .jsp contains, and i would like to translate this to be in .java/.class format:
<%@ page import="sun.misc.BASE64Encoder, javax.crypto., javax.crypto.spec."%>
<%@ page import="java.util.StringTokenizer" %>
<%@ page import="java.util.Map" %>
<%!
sb.append("<input type=\"hidden\" name=\"orderPage_serialNumber\" value=\"");
sb.append(serialNumber);
sb.append("\">\n");
return sb.toString();
%>
how can i translate the above import statements and html elements from jsp to java, please let me know.
Once i have the .java file created from the .jsp, I will compile .java to create the .class file and invoke the .class in peoplecode by using java apis available in peopletools.
Thanks in advance.

Is there a way convert a binary .exe file( compiled by
another compiler) into Java .class/.jar file ? Anyone
know of a free program that can do this?It's not possible. There are many decompilers and disassemblers for Java but nothing will take you from ANY binary to Java source. It would be the end of computing as we know it and the beginning of a new era -:)

How to convert dll to a java class file?

Hi folks:
I have some DLLs in VB and C++ and I wanna to convert them to a java class file. Does anybody know if exist a sw or easy way to do it?
thanks
Autair

Well, I believe you could write JNI to call the functions in the DLLs, although I wouldn't recommend it. (You'd have a non-portable, fragile result.)

How to convert java .class file to .dll file

hi,
I got a problem, I have to convert my java .class file to .dll file. Microsoft VC++ program will invoke the converted .dll file.
Is there any other possibility.
I was confused.
Cam any body help me. If you are having solution for the can you send to my [email protected] account.
thanks,

No, it is not possible to do what you are suggesting. Yes, you could produce a DLL that wraps the JVM and loads your java class exposing a C and/or C++ callable interface, but that is a lot to go through unless your class is VERY complex. Otherwise, you might want to just create and maintain two implementations.

How can I share a *.java source file across multiple projects in NetBeans?

I'm sure this simple and a pretty common operation but how can I share a *.java source file across multiple projects in NetBeans? Right now I keep cut, coping and pasting the same source file between multiple projects to re-use the same code. But I could I make this source file a library file or something like that so that I could access it from any project. I assume this would be a generic operation but I mentioned NetBeans for clarity. Thanks.

fiebigc wrote:
I know I mentioned NetBeans but I'm most interested in the generic method for creating a library of source files that I can call into whatever program I am developing. I've done such a thing in C using header files and such but I'm trying to get a direction on how this is accomplished in Java. I'm sorry if I could edit the title I would. If anyone wants to be specific about NetBeans I welcome that too.
Edited by: fiebigc on Jun 20, 2008 5:57 PM
>I know I mentioned NetBeans but I'm most interested in the generic method for creating a library of source files that I can call into whatever program I am developing. I've done such a thing in C using header files and such but I'm trying to get a direction on how this is accomplished in Java. I'm sorry if I could edit the title I would. If anyone wants to be specific about NetBeans I welcome that too.
Edited by: fiebigc on Jun 20, 2008 5:57 PM
Create a class library.
Write your code, compile it to .class files, put those class files in a .jar file and include the jar file in the classpath whenever you want to compile a project against it.

How can i run a java class file from shell?

Hi all,
I've a .class file named "File" that contains Main method, it is in the package "File2".
How can I run it by shell command?
PS: "java -cp . file" doesn't work it launch->
Exception in thread "main" java.lang.NoClassDefFoundError: File2/File (wrong name: File2/File)
Thanks in advance.

Just to understand: is File2 ar jar archive or not? If it is a jar archive, have you tried open File2.jar? If File2 is a directory within the current directory, have you tried java -cp . File2/File? I just tested with a set of classes and it works... Let me be precise:
* Let us imagine you are working in a directory whole path is PathToDir/
* in this directory you have the classes put in a directory called File2
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cd PathToDir/ (just to be sure)
java -cp . File2/File
*if you were to do the following then you would have the problem you describe
cd PathToDir/File2/
java -cp . File

Static lookup lists:read data from a Java *.properties file

Hi
i need to make static lookup lists i am using read data from a Java *.properties file
i am using the Class "PropertyFileBasedLookupViewObjectImpl" that wrote by Steve Muench in ToyStore.
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String temp=Locale.getDefault().getLanguage();
String propertyFile =
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Depending on your use case you can either use a programmatic VO or directly expose the JV class as a data control.
http://docs.oracle.com/cd/E18941_01/tutorials/jdtut_11r2_36/jdtut_11r2_36.html

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i have a java package which reads values from property file. i have imported the package.classname in jsp file and also i have created an object for the class file like
classname object=new classname();
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in jsp i need to use
statement=con.createstatement(); but it shows variable not declared.
con is declared in java class file.
how to access the variables?
thanks

here is the code
* testbean.java
* Created on October 31, 2006, 12:14 PM
package property;
import java.beans.*;
import java.io.Serializable;
public class testbean extends Object implements Serializable {
public String sampleProperty="test2";
public String getSampleProperty() {
return sampleProperty;
}jsp file
<%@ page contentType="text/html;charset=windows-1252"%>
<%@ page import="java.sql.*,java.util.*"%>
<html>
<head>
<title>Schedule Details</title>
</head>
<jsp:useBean id="ConProp" class="property.testbean"/>
<body>
Messge is : <jsp:getProperty name="msg" property="sampleProperty"/>
<%
out.println(ConProp.sampleProperty);
%>
</body>
</html>out.println(ConProp.sampleProperty) prints null value.
is this the right procedure to access bean variables
thanks

Java.io.File.renameTo

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