Back to .class file

hello all,
I'm not big into java yet, but I have a script I'm playing around with that I decompiled from a .class file and moved things around a bit... now I want to compile it back to a .class file and have no idea how. I can't seem to find a freeware program to do it with.
please excuse my newbiness...
thanks for the help
ziggy

Start with this tutorial http://java.sun.com/docs/books/tutorial/getStarted/cupojava/index.html
Do not skip anything, and be sure to read the Installation Instructions (there's a link), especially #5, and set the PATH variable as instructed.
It will lead you through installing and learning to use the compiler, then running a program.

Similar Messages

Thiz iz Urgent..........How to convert a .class file to a .java file

Hi Everybody,
I want to convert back a .class file (a compiled servlet) into .java (source code) file. How do I do it???
Note using javap has not been of any help.
Thanks in Advance
Rajib

Why don't you look at this thread:
http://forums.java.sun.com/thread.jsp?forum=31&thread=143500
If thats not enough, try searching all the forums for:
"convert .java .class" That'll give yu a bunch of other threads...
Sjur

How to convert JSP Compiled class file back to JSP

Is their any way to convert the JSP converted class file back into JSP file, I have few JSP files missing in my application but i do have class files deployed corresponding to the JSP file. Is their any way where i can convert my JSP class file back to JSP. I tried used decompliers but it conerts the class file into JAVA files, Is their any such decompiler that converts the JSP converted class file into Java files.
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nope...its not et al possible...!!!
You cant convert class file back to JSP....!!

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any pointers on how to do it then ? i don't have
access to the native codeIf I have understood you correctly, you have native code that generates bytecode. Currently you load the class this bytecode represents right into the classloader, but you want to save it to disk as a .class file. Right?
If so, you just have to get hold of that bytecode before it "disappears" into the classloader, and save it to disk. How you can best do this depends on exactly how you communicate with that native code.
If I have misunderstood your problem (and that's not unlikely), please try to be clearer.

Is it possible convent .Class file back to .java file? or human readalbe .

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Search for jad decompiler then install into what ever directory you wish.
Its dos base so copy what ever .class into the jad directory then
in command prompt go to the directory with jad, run jad then type
jad -s<java> <filename>.class
It is a very good program

Conversion of a .jar OR a .class file into a .exe file

Can anyone tell me as how to convert a .jar OR a .class file into a .exe file
I need to know as soon as possible.

Okay I will tell you the steps:
Look in the top right hand corner of the page.
There should be a box with a red title line. Inside the
title should be the letters 'S E A R C and H'.
In the white part of th box should be a smaller line, in which you can type.
type in "conversion .jar .class .exe" or some similar string.
Then click on the button next to the text box.
Read the page of results you get.
Click on the first link and read what is said on the connecting page.
If that doesn't help, use your browser's back button and click on the next link, and repeat util your question is answered.

Convert .class files into .java files???

Does anybody know how to convert x.class file back to a x.java file. Or in other terms, extract .java files from a jarfile??
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/carlos

Does anybody know how to convert x.class file back to a x.java file.As Dr.Clap said, that's decompiling.
Or in other terms, extract .java files from a jarfile??That isn't quite the same thing. You can decompile a .class that's in a jar, but a .class file doesn't have to be in a jar and a file in a jar isn't necessarily a .class.

How do I make a batch file if the .class file uses a foreign package?

I am trying to make an MS-DOS batch file using the bytecode file from the Java source file, called AddFields.java. This program uses the package BreezySwing; which is not standard with the JDK. I had to download it seperately. I will come back to this batch file later.
But first, in order to prove the concept, I created a Java file called Soap.java in JCreator. It is a very simple GUI program that uses the javax.swing package; which does come with the JDK. The JDK is currently stored in the following directory: C:\Program Files\Java\jdk1.6.0_07. I have the PATH environment variable set to the 'bin' folder of the JDK. I believe that it is important that this variable stay this way because C:\Program Files\Java\jdk1.6.0_07\bin is where the file 'java.exe' and 'javac.exe' are stored. Here is my batch file so far for Soap:
@echo off
cd \acorn
set path=C:\Program Files\Java\jdk1.6.0_07\bin
set classpath=.
java Soap
pause
Before I ran this file, I compiled Soap.java in my IDE and then ran it successfully. Then I moved the .class file to the directory C:\acorn. I put NOTHING ELSE in this folder. then I told the computer where to find the file 'java.exe' which I know is needed for execution of the .class file. I put the above text in Notepad and then saved it as Soap.bat onto my desktop. When I double click on it, the command prompt comes up in a little green box for a few seconds, and then the GUI opens and says "It Works!". Now that I know the concept of batch files, I tried creating another one that used the BreezySwing package.
After I installed my JDK, I installed BreezySwing and TerminalIO which are two foreign packages that make building code much easier. I downloaded the .zip file from Lambert and Osborne called BreezySwingAndTerminalIO.zip. I extracted the files to the 'bin' folder of my JDK. Once I did this, and set the PATH environment variable to the 'bin' folder of my JDK, all BreezySwing and TerminalIO programs that I made worked. Now I wanted to make a batch file from the program AddFields.java. It is a GUI program that imports two packages, the traditional GUI javax.swing package and the foreign package BreezySwing. The user enters two numbers in two DoubleField objects and then selects one of four buttons; one for each arithmetic operation (add, subtract, multiply, or divide). Then the program displays the solution in a third DoubleField object. This program both compiles and runs successfully in JCreator. So, next I moved the .class file from the MyProjects folder that JCreator uses to C:\acorn. I put nothing else in this folder. The file Soap.class was still in there, but I did not think it would matter. Then I created the batch file:
@echo off
cd \acorn
set path=C:\Program Files\Java\jdk1.6.0_07\bin
set classpath=.
java AddFields
pause
As you can see, it is exactly the same as the one for Soap. I made this file in Notepad and called it AddFields.bat. Upon double clicking on the file, I got this error message from command prompt:
Exception in thread "main" java.lang.NoClassDefFoundError: BreezySwing/GBFrame
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:12
4)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
at java.net.URLClassLoader.access$000(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
Caused by: java.lang.ClassNotFoundException: BreezySwing.GBFrame
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
... 12 more
Press any key to continue . . .
I know that most of this makes no sense; but that it only means that it cannot find the class BreezySwing or GBFrame (which AddFields extends). Notice, however that it does not give an error for javax.swing. If I change the "set path..." command to anything other than the 'bin' folder of my JDK, I get this error:
'java' is not recognized as an internal or external command,
operable program or batch file.
Press any key to continue . . .
I know this means that the computer cannot find the file 'java.exe' which I believe holds all of the java.x.y.z style packages (native packages); but not BreezySwing or any other foreign packages. Remember, I do not get this error for any of the native Java packages. I decided to compare the java.x.y.z packages with BreezySwing:
I see that all of the native packages are not actually visible in the JDK's bin folder. I think that they are all stored in one of the .exe files in there because there are no .class files in the JDK's bin folder.
However, BreezySwing is different, there is no such file called "BreezySwing.exe"; there are just about 20 .class files all with names like "GBFrame.class", and "GBActionListener.class". As a last effort, I moved all of these .class files directly into the bin folder (they were originally in a seperate folder called BreezySwingAndTerminalIO). This did nothing; even with all of the files in the same folder as java.exe.
So my question is: What do I need to do to get the BreezySwing package recognized on my computer? Is there possibly a download for a file called "BreezySwing.exe" somewhere that would be similar to "java.exe" and contain all of the BreezySwing packages?

There is a lot of detail in your posts. I won't properly quote everything you put (too laborious). Instead I'll just put your words inside quotes (").
"..there are some things about the interface that I do not like."
Like +what?+ This is not a help desk, and I would appreciate you participating in this discussion by providing details of what it is about the 'interface' of webstart that you 'do not like'. They are probably misunderstandings on your part.
"Some of the .jar files I made were so dangerously corrupt, that I had to restart my computer before I could delete them."
Corrupt?! I have never once had the Java tools produce a corrupt Jar. OTOH, the 'cannot delete' problem might relate to the JRE gaining a file lock on the archive at run-time. If the file lock persisted after ending the app., it suggests that the JRE was not properly shut down. This is a bug in the code and should be fixed. Deploying as .class files will only 'hide' the problem (from casual inspection - though the Task Manager should show the orphaned 'java' process).
"I then turned to batch files for their simple structure and portability (I managed to successfully transport a java.util containing batch file from my computer to another). This was what I did:
- I created a folder called Task
- Then I copied three things into this folder: 1. The file "java.exe" from my JDK. 2. The program's .class file (Count.class). and 3. The original batch file.
- Then I moved the folder from a removable disk to the second computer's C drive (C:\Task).
- Last, I changed the code in the batch file...:"
That is the +funniest+ thing I've heard on the forums in the last 72 hours. You say that is easy?! Some points.
- editing batch files is not scalable to 100+ machines, let alone 10000+.
- The fact that Java worked on the target machine was because it was +already installed.+ Dragging the 'java.exe' onto a Windows PC which has no Java will not magically make it 'Java enabled'.
And speaking of Java on the client machine. Webstart has in-built mechanisms to ensure that the end user has the minimum required Java version to run the app. - we can also use the [deployJava.js|http://java.sun.com/javase/6/docs/technotes/guides/jweb/deployment_advice.html#deplToolkit] on the original web page, to check for minimum Java before it puts the link to download/install the app. - if the user does not have the required Java, the script should guide them through installing it.
Those nice features in deployJava.js are available to applets and apps. launched using webstart, but they are not available for (plain) Jar's or loose class files. So if 'ensuring the user has Java' is one of the requirements for your launch, you are barking up the wrong tree by deploying loose class files.
Note also that if you abandon webstart, but have your app. set up to work from a Jar, the installation process would be similar to above (though it would not need a .bat file, or editing it). This basic strategy is one way that I provide [Appleteer (as a downloadable ZIP archive)|http://pscode.org/appleteer/#download]. Though I side-step your part 1 by putting the stuff into a Jar with the path Appleteer/ - when the user expands the ZIP, the parts of the app. are already in the Appleteer directory.
Appleteer is also provided as a webstart launched application (and as an applet). Either of those are 'easier' to use than the downloadable ZIP, but I thought I would provide it in case the end user wants to save it to disk and transport the app. to a machine with no internet connection, but with Java (why they would be testing applets on a PC with no internet connection, I am not sure - but the option is there).
"I know that .jar and .exe files are out because I always get errors and I do not like their interfaces. "
What on earth are you talking about? Once the app. is on-screen, the end user would not be able to distinguish between
1) A Jar launched using a manifest.
2) A Jar launched using webstart.
3) Loose class files.
Your fixation on .bat files sounds much like the adage that 'If the only tool you have is a hammer, every job starts to look like a nail'.
Get over them, will you? +Using .bat files is not a practical way to provide a Java app. to the end user+ (and launching an app. from a .bat looks quite crappy and 'second hand' to +this+ user).
Edit 1:
The instructions for running Appleteer as a Jar are further up the page, in the [Running Appleteer: Application|http://pscode.org/appleteer/#application] section.
Edited by: AndrewThompson64 on May 19, 2009 12:06 PM

Than how can i get java class by using it's class file?

Hi
After compilation of a java program, it creates a class file.
After getting class file suppose class file has been deleted.
Than how can i get java class by using it's class file?
Thanks in advance.

get a decompiler and run your class file through it--I'll assume you want the source code back and that you are not trying to recover a missing class file by attempting to use the class file that is missing--if it's missing, then I've not a clue on how to get it back by using what is already missing.
BTW: many of your compilers have source control--if it does, just restore your missing file.

How to include a .class file in a jsp page

hi everyone,
i know the syntax as:
<%@ include file = "filename.class" %>
then at run time the server could not find the class file
if i use,
<%@ page import = "FileName.class" %>
then also the same problem persists
& if i use
<jsp:include page = "Relative address"/>
the problem still remains as it is...
please help me out...i am working on developing an EJB application in which client interacts with server's Stateful session bean through a jsp page...it is necessary for me to include the home interface class file in my jsp page.
P.S. do not suggest me to include the class file in a package & then use
<%@ page import = "packageName.ClassFileName" %>
i
Edited by: Ankit_JIITU on 6 Jul, 2008 1:55 AM

Ankit_JIITU wrote:
i have already included the remote interface class file by <%@ page import = "University.RemoteInterfaceName" %>in my jsp page ...
if i try to make a new package called test & then include my home interface in that package...i need to import University.*to generate the class file of my home interface ; but the class file generation is not taking place as i am getting the error..
"package University does not exist".How can i overcome this problem. The package University, which you are trying to import, must be in the classpath. If you removed it then you will have to add it back.
i have tried my best..but tell me if there's any possible way of including a class file in the jsp page without involving a package.No, there isn't.
If not,then pls help me to generate the class file of my home interface within a package called test.Read the New To Java Tutorial and understand how packages work.
>
i am assuming that u have a deep knowledge of developing EJB applications.

LMS 3.2 - Backup-Error -- ERROR(908): Cannot create or back up tar file

Hello again,
with performing backup (LMS 3.2 on Solaris 9) the following errors will arise.
dbbackup.log
/opt/CSCOpx/bin/tar: Removing leading `/' from absolute path names in the archive Apps file : /opt/CSCOpx/backup/manifest/upm/upminfo/datafiles.txt
[Tue Dec 8 08:56:54 2009] Archiving the contents of the following directories into /enbw/backup/files/cw_db_backup/0/upm/filebackup.tar
[Tue Dec 8 08:56:54 2009] /opt/CSCOpx/hum/conf/upm-snmp.properties
/opt/CSCOpx/hum/thresholdscript /opt/CSCOpx/MDC/tomcat/webapps/upm/reports
/opt/CSCOpx/MDC/tomcat/webapps/upm/WEB-INF/classes/com/cisco/nm/upm/properti
es/common/UPM.properties
/opt/CSCOpx/bin/tar: Removing leading `/' from absolute path names in the archive
/opt/CSCOpx/bin/tar: Cannot add file
/opt/CSCOpx/MDC/tomcat/webapps/upm/reports/virt32841308_657_658_-718594975:
No such file or directory
/opt/CSCOpx/bin/tar: Cannot add file
/opt/CSCOpx/MDC/tomcat/webapps/upm/reports/virt32841308_658_659_1465769167:
No such file or directory
/opt/CSCOpx/bin/tar: Error exit delayed from previous errors [Tue Dec 8 09:07:30 2009] ERROR(908): Cannot create or back up tar file. Backup cancelled. Verify that you have write-access to this directory. [Tue Dec 8 09:07:30 2009] Backup failed: 2009/12/08 09:07:40 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Is seems to be problem related to maximal filesize handling of GNUtar implemented in CW2000.
The problem is with tar'ing HUM-Reports in /opt/CSCOpx/MDC/tomcat/webapps/upm/reports, and with reaching
tarfile-size of 2,9GByte error is thrown.
</exxx/backup/files/cw_db_backup/0/upm># ls -lh
total 6126448
-rw-r-----   1 casuser casusers    2.9G Dec 8 09:07 filebackup.tar
</exxx/backup/files/cw_db_backup/0/upm># ls -al
total 6126452
drwxr-x---   2 casuser casusers     512 Dec 7 14:30 .
drwxr-x--- 11 casuser casusers     512 Dec 7 14:30 ..
-rw-r-----   1 casuser casusers 3135201280 Dec 8 09:07 filebackup.tar
GNUtar-Version
# /opt/CSCOpx/bin/tar --version
tar (GNU tar) 1.13
Copyright (C) 1988, 92,93,94,95,96,97,98, 1999 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by John Gilmore and Jay Fenlason.
Is this a know problem?
Thanks for any thoughts.
Best Regards
Lothar

Hi Joe,
thanks for your feedback.
These files to be tarred aren't there directly after backup stops with error.
It seems that some process stores data about reports in that file and when trying to
pack these reports via tar they are delete by any cleanup method.
Does this help.
P.S. Backup usually takes about more than 1hour

Error Message When Using a Class Files to Control Navigation

This is my first attempt at using a class file in a flash project. My intent is to keep all of my navigation elements in class file called "Navigation". However, I keep getting an error message when I publish.
I am using a button to go back to the main screen and I gave that button the instance name of "bnt_home". I have also linked that button in the library to the class "Navigation".
Here is the code:
package
    import flash.display.SimpleButton;
    public class Navigation extends SimpleButton
        public function Navigation()
            bnt_home.addEventListener(MouseEvent.MOUSE_DOWN, goNavigation);
        private function goNavigation(event:MouseEvent):void
            gotoAndPlay(1,"Main");

When I changed the code I got error (1046: Type was not found or was not a compile-time constant: MouseEvent).
package
    import flash.display.SimpleButton;
    public class Navigation extends SimpleButton
        public function Navigation()
            this.addEventListener(MouseEvent.MOUSE_DOWN, goNavigation);
        private function goNavigation(event:MouseEvent):void
            root.gotoAndPlay(1,"Main");

Organizing class files (in the filesystem)

Hi, I'm new to Java and the JDC. I have run into one issue, in my explorations in Java, and that is organizing the class files and source code files. I understand that I can organize them in any way that I like, but I was curious if there is a standard system that other Java developers use (like the /usr/local convention on Unix).
Should I create a /usr/local/java directory and then store class and source files in subdirectories of that? And then add the class directory to the CLASSPATH? How about downloaded source code that I didn't write -- that seems like it would then go in yet another directory.
So far I've got everything stored in ~/dev/java (a directory I created for this purpose), but it seems like it's bound to get unmanageable if I don't order it better. And I'm just curious what others with more experience do.
Thanks!
Erik

Anyway, back to why. If as you mentioned you keep all of your class files off a given root folder, then you can add that folder root to the classpath.
Okay, I have the domain "erikprice.com". So then I would create a hierarchy like this (?) :
- ~
- dev
    - Java
      - com
        - erikprice
          - packageA
          - packageB
          - packageC
             ...etc...And then, if I add ~/dev/Java/com to my CLASSPATH, all of the classes in the various packages below that will be accessible to the compiler? Or do I have to explicitly put ~/dev/Java/com/erikprice into the classpath?
Also, if I have downloaded someone else's source code (such as a Jakarta project or something), it seems like I should put its root folder in with my personal root folder. In other words, like this:
- ~
- dev
    - Java
      - com
        - erikprice
      - org
        - apache
          - xml
            - xerces
              - packageA
              - packageB
            - xalan
              - packageA
              - packageB
              ...etc...Does this seem right? If I understand correctly, I will have to add the org directory to the CLASSPATH too. Can I save all of this trouble by putting just ~/dev/Java into the CLASSPATH so that all of the packages below (com/erikprice/*, org/apache/xml/*, org/someotherproject/*) are available?
The trick of this is that I'm trying to organize both my own Java files as well as those that I've downloaded to study from. Thanks for your input, MLangstaff.

How to save library symbols' class files in packages that are not the default package?

Hi,
I perform the following in Flash CS5 with Flash Builder 4
1) Create a new library symbol.
2) Do a RightClick->Properties on the new symbol
3) Check the options for "Export for ActionScript" and "Export in frame 1".
4) I write a new name for my class "Class1" and click on the pencil icon "edit class definition" to edit the class.
At this point my FlashBuilder 4 takes over and opens the "New ActionScript" dialog.
4) I then click on Package-Browse to select a package e.g. com.mycompany.myfiles as the new class destination.
The as file is created as com.mycompany.myfiles/Class1.as as everything seems just fine.
5) I close the ActionScript file and back in Flash CS5 I RightClick on the symbol and select "Edit Class".
At this time, FB4 suggests again to create the file, ignoring the fact that I already created it before.
Do you know of a way I can make Flash CS5 remember where I created the file?
Thanks.

Hi,
I didn't remove the project or delete any of the files.
All I did was create the class file under a package that is not the default package. Then when I clicked on the Flash symbol's "Edit Class" It asked me again to create the same class file.
Only if I create the class in the default package, it won't ask me to recreate it again.
Bye,
RaamEE-IL

Trouble writing pixel array back to gif file

Hi everyone. I am in the middle of constructing a steganography api for a final year group project. I have taken out the pixels into an array from a gif file. I am having trouble writing it back to a gif file. Here is my code:
import javaSteg.stegoLibrary.*;
import java.awt.*;
import java.awt.image.*;
import java.io.*;
import Acme.*;
import Acme.JPM.Encoders.*;
public class Gif extends Canvas{
     public void encodeGif(byte[] imageData){
          //create toolkit obarrayPointerect
          Toolkit t = Toolkit.getDefaultToolkit();
          MediaTracker tracker = new MediaTracker(this);
          //decode specified Gif cover
          Image img = t.createImage(imageData);
          tracker.addImage(img,0);
          try{
               tracker.waitForAll();
          catch(InterruptedException e){
          System.out.println("Tracker interrupted.");
          //retrive picture from image
          int[] pix = new int[img.getWidth(this) * img.getHeight(this)];
          PixelGrabber pg = new PixelGrabber(img, 0, 0, img.getWidth(this), img.getHeight(this), pix, 0, img.getWidth(this));
          try{ pg.grabPixels();
          } catch (InterruptedException ioe) {
               System.err.println("Interrupted");
          if ((pg.getStatus() & ImageObserver.ABORT) != 0) {
          System.err.println("image fetch aborted or errored");
          return;
          //put into byte array
          byte[] pixels = new byte[img.getWidth(this) * img.getHeight(this)];
          for(int arrayPointer=0;arrayPointer<pix.length;arrayPointer++){
               pixels[arrayPointer] = new Integer(pix[arrayPointer]).byteValue();
          //edit pixels not implemented yet
//assign edited pixels to an image
          img = t.createImage(pixels);
          // Now encode the image using ACME free GIF encoder (www.acme.com)
          try{
               FileOutputStream fos = new FileOutputStream("D:\\result.gif");
               GifEncoder encoder = new GifEncoder(img, fos);
               encoder.encode();
               fos.close();
          }catch(IOException e) {
          System.out.println("FATAL IOException "+e);
From this i get a single pixel in my output gif file. Is there a way of swapping out the edited pixels with the origonal pixels in the image file? or an alternative way to write back the complete file.
Thanks a lot
MickyT

ive managed to solve it. For those who come across this thread and want to know the solution i needed to use MemoryImageSource with the pixels inorder to pass them to the createImage method :o)

Back to .class file

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