Protecting your jar file from been extracted

Please i noticed that the java jar file of a software can easily be extracted to review the class files with winrar which allows just anyone to have access to your class file and decompile to get source codes, allowing pirating of the software. How can I lock the jar file to prevent extraction of my class files.

1. why are you mocking others instead of answering the question ? some one wants to protect his jar file. the solution is simple.
2. you can use google to search, here is result :
http://stackoverflow.com/questions/1280702/protecting-java-jar-files-for-distribution
http://stackoverflow.com/questions/9633455/how-to-protect-a-jar-file-from-being-decompiled
http://www.thegeekstuff.com/2008/06/protect-your-java-code-from-reverse-engineering/
http://answers.google.com/answers/threadview/id/431511.html
http://stackoverflow.com/questions/1879061/how-to-protect-java-codes-against-decompiler
http://viralpatel.net/blogs/2009/07/protect-java-code-decompilation-using-java-obfuscator.html
http://www.coderanch.com/t/430716/java/java/Protect-class-file-not-decompile
http://stackoverflow.com/questions/7324708/are-jar-file-insecure-what-can-done-apart-from-code-obfuscation
http://stackoverflow.com/questions/3647255/how-do-i-copy-protect-my-java-application
http://www.javaworld.com/javaworld/javatips/jw-javatip22.html
http://stackoverflow.com/questions/12088/do-you-obfuscate-your-commercial-java-code
3. it is true if you can use basic methods that EJP mentioned, there would be no need for obfuscators, nor native library use.
but there are many situations that you can't do any of those methods.
4. EJP claims that he probably is the one "who have had perhaps 40 times as long as you've had to think about it."
here is the problem that made me use both obfuscation and native library :
My company released a simple java library that scanned a document (directly from scanner or camera device).
the documents were exam papers.
Use some OCR techniques to convert image to text so some other application could calculate the score using it's api.
For marketing purposes, the company needed to publish a 7-day trial version of this library.
So, as you can see I'm eager to hear what you want to suggest.

Similar Messages

How to protect my jar file from being downloaded

How can i protect my jar file from being downloaded by users by accessing it through the web site.
Now everybody can just type the url www.mysite.com/applets/myApplet.jar
And download it to his computer.
I realize that anybody who really wants to download it he will get it anyway, but I want to make it harder.
thanks in advance

Your browser has to download the jar file if it's going to run the applet. That's applets work. The browser downloads the classes and then runs them locally.
I suppose if you wanted to make something to make it difficult for users to explicitly download the jar, you could set some kind of permission flag when the HTML is page is rendered, and then unset it some amount of time (10 seconds?) later, and then only let the user download the jar when the flag is set. But this would be fragile and irritating and unhelpful. It would probably break more than you'd like and not prevent download very much (it wouldn't take long to figure out what was happening), and besides nobody is ever going to try to steal your code.

Protecting Java jar files from decompiling.

Hello,
I need to distrubute ny Java application, I know there are tools to reengineer the java class file. How to Protect my class files from exploitation.
Any suggestions.
Thanks
Shreenivasa

1. Write a no-decompile clause into the licence.
2. Make your product so expensive that no licensee will want anybody else to get one for nothing.
3. Make your product so inexpensive that it would be simpler to buy it than reverse-engineer it.
4. Bring out new versions of your product so rapidly or with such amazing new features in each release that the reverse-engineers can't keep up with you.
5. Make a proper evaluation of the forgone revenue against the cost of all this engineering, that doesn't assume you would have sold a copy to every potential pirate, or that you can actually deter every potential pirate.
In short it is a business problem. Not a technical problem.

Protecting the jar files from being web access

I have a jnlp file which is put under tomcat webapps folder, say (\webapps\TEST\launch.jnlp), with the jar and lib files put in the subfolder (\webapps\TEST\folder1\*.jar AND \webapps\TEST\folder1\lib\*.jar).
My question is how can i prevent user from direct access to the jar files via typing http://www.someip.com/TEST/folder1/main.jar ? I tried the following methods but it seemed not working:
1. Change the folder permisson in \webapps\TEST\*.*, but when user type the above hyperlink they can still get the jar file
2. put the jar and related files under \WEB-INF\, but now this time running the launch.jnlp, it returns an error saying that it can't access/find the WEB-INF.
Is there any method? Or should I say, when you published jnlp to web, the related jar files are forced to be accessed by everyone.

Sounds easy to me: encrypt your xml, then instead of just storing your key as plain bytes do some reversable operations on it (xor masks, reversions, whatever you like), just do them in many different points (and classes) of your code, have some parts done by methods that actually check application is running under JWS with proper codebase, scramble it all, and suddently the whole stealing operation won't be worth the effort. Obviously you should have many private (and package protected) methods, seal packages and so on. Maybe, somehow, you can even use reflection to identify calling classes (not sure, never looked for anything similar).
What else? write down some c++ code into your own dll/JNI library and make it do something too, so they'll even need to decompile the dll. If you know first execution is always online you can send another xor key and store it with persistence service or write it down to windows registry. You can keep making it harder as much as you like, even just with silly code like
Math.ceil((new GregorianCalendar.getField(Calendar.YEAR)%2000)/1000)*((int)('c'-'a'))just to retrieve the number 2. If you distribute such code through many lines and methods, once you scramble it, most people will give up.
Bye.

Is it possible to call a class in a jar file from JNI environment?

Hi
Is it possible to call a class in a jar file from JNI environment?
Thanks in advance.

Could you explain a bit more what you are trying to do? (In other words, your question is vague.)
o If your main program is written in C, you can use JNI to start a JVM, load classes from the jar of your choice, and call constructors and methods of the objects defined in the jar.
o If your main program is java, and has been laoded from a jar, a JNI routine can call back into java to use the constructors and methods of classes defined in the jar(s).

How to know if the current application jar file has been overwritten?

When I overwrite a jar file that is being used, the buttons that call new windows stop responding silently but is there some check I can make from within the application to know if the jar file has been overwritten, so that I can warn the user to restart it?
I know this sounds bad so let me explain why I would want this, if you don't care then skip everything below this point.
I have close to a hundred of users executing Java applications from a central repository in the network. This is important because the applications are always changing and evolving so it's important that I only have to update one binary. I do most updates after work hours so I don't have a problem there but sometimes there are critical errors that need to be corrected immediately. Depending on the amount of people using an application it may be impractical to warn and wait for everyone to close it and make everyone else wait for that so I just overwrite the files that need to be updated and then warn everyone to restart the application. The result is that buttons that call for frames that haven't been called yet stop working silently. Some users already know what to do when that happens but I want a more graceful approach. I wanted to check for this situation from inside the application so that I could inform the user of the update and provide information on what to do next. Can I do this? I tried some try and catch blocks of code but I can't seem to catch anything when that happens.

You can write your own class loader that loads classes from that jar file. Make sure it isn't on the class path and when you want to create an object from that jar file, call up your class loader to do that. (You only have to do that for your "top-level" objects, within those objects creating another object will automatically be done by your class loader.)
Periodically check whether the jar has been modified. If it has, refresh the application by creating a new instance of your class loader and using that to create new instances of all your objects.
But that sounds like a lot of work just to avoid setting up an emergency change procedure where you get everybody to close their applications.

Can't run JavaFX app as a jar file from command line

I'm trying to build a JavaFX app from scratch (that is, by including the jar file from the JavaFX SDK rather than by using the special JavaFX project type from NetBeans). It runs fine in NetBeans. However, when I try to launch it as a jar file from the command line (using "java -jar dist\TestApp") I get the following. Has anybody seen this before, and if so how can I fix it?:
*** Fallback to Prism SW pipeline
Exception in thread "main" java.lang.RuntimeException: java.lang.UnsatisfiedLink
Error: Can't load library: C:\dev\TestApp\dist\bin\mat.dll
at com.sun.javafx.tk.quantum.QuantumToolkit.startup(QuantumToolkit.java:
289)
at com.sun.javafx.application.PlatformImpl.startup(PlatformImpl.java:68)
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherIm
pl.java:145)
at com.sun.javafx.application.LauncherImpl.access$000(LauncherImpl.java:
27)
at com.sun.javafx.application.LauncherImpl$1.run(LauncherImpl.java:97)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.UnsatisfiedLinkError: Can't load library: C:\dev\RedactionT
oolPrototype\RedactionToolPrototype.Core\dist\bin\mat.dll
at java.lang.ClassLoader.loadLibrary(Unknown Source)
at java.lang.Runtime.load0(Unknown Source)
at java.lang.System.load(Unknown Source)
at com.sun.glass.utils.NativeLibLoader.loadLibraryFullPath(NativeLibLoad
er.java:155)
at com.sun.glass.utils.NativeLibLoader.loadLibraryInternal(NativeLibLoad
er.java:85)
at com.sun.glass.utils.NativeLibLoader.loadLibrary(NativeLibLoader.java:
30)
at com.sun.glass.ui.Application$1.run(Application.java:28)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.glass.ui.Application.loadNativeLibrary(Application.java:26)
at com.sun.glass.ui.win.WinApplication.<clinit>(WinApplication.java:33)
at com.sun.glass.ui.win.WinPlatformFactory.createApplication(WinPlatform
Factory.java:20)
at com.sun.glass.ui.win.WinPlatformFactory.createApplication(WinPlatform
Factory.java:17)
at com.sun.glass.ui.Application.Run(Application.java:51)
at com.sun.javafx.tk.quantum.QuantumToolkit.startup(QuantumToolkit.java:
279)
... 5 more

Unsatisfied link means that Java is trying to access a native library, but it cannot be found. As to why this error is being thrown, here is my guess:
If you open up one of the sample jars with a zip viewer, you will see that the Manifest file has the following entries:
>
Manifest-Version: 1.0
JavaFX-Version: 2.0
implementation-vendor: Oracle
implementation-title: BrickBreaker
implementation-version: 1.0
JavaFX-Application-Class: brickbreaker.Main
Created-By: JavaFX Packager
Main-Class: com/javafx/main/Main
>
In other words, a JavaFX project works a bit differently than a normal Java project. com/javafx/main/Main is used as the Main class and your "Main" class is called later.
If you are trying to build this from a normal Java project, then com/javafx/main/Main will not be created and it will call your Main class right away. Thus, whatever setup is needed to run JavaFX will not occur.

Multiple jar files from different locations

Hello,
I am having an applet that access code from two different jar files. Of them one is a common jar file for many applets. So I couldn't place it in the local dir as that of the applet's html. I am not using any web server.
     Just to give you a feel of it :
     <PARAM NAME = archive VALUE = "DVApplet.jar,DVVP.jar" > are the jar files my applet is dependant on. But DVVP.jar has to be accessed from a dir different from local dir.
     Will be glad if someone can throw some light on accessing different jar files from different dirs.
     Thanks for your time.
Regards,
Anantha

[url=
http://forum.java.sun.com/thread.jsp?forum=421&thread=425724&tstart=0&trange=100
]This question is a bit similar
You can use a class loader to do such things.

Access jar file from in-memory classes...

I have some classes that I compile to memory and everything works fine until one class that must access some external jar files. I have been unable to access those jar files from disk after trying every suggestion using URLClassLoader. I even tried someone's example to hack the SystemClassLoader which properly adds the jar file paths, but still they can't be seen. The only way it works is if I put the files in the jdk/jre/lib/ext directory. Then everything works fine. There must be a way to load the jar files in memory as well as the class files so they can be accessible. Has anyone done anything like this? Is it possible? Even though the class files are in memory, why would the jar files not be seen even when they are added to the same URLClassLoader's URL's. Thanks.

Sorry that wasn't clear. What I mean is that the classes are compiled to byte code directly to memory and no physical .class file is created. Yes, I'm using my own ClassLoader that extends URLClassLoader and I'm setting the parent to ClassLoader.getSystemClassLoader(). I also should mention that I'm doing this inside a Netbeans module that is part of a Netbeans Platform application. I don't know why that should matter though, since I'm trying to do everything in memory without creating the physical files. Thanks.

Getting Exception in JWS while downloading jar files from server

Hi All,
I am running JWS on j2re1.4.2_10(build 03). while JWS is trying to download jar files from web server, I am getting the following Exception.
All the jar files are signed. Any idea ?
JNLPException[category: Download Error : Exception: null : LaunchDesc: null ]
     at com.sun.javaws.cache.DownloadProtocol.doDownload(Unknown Source)
     at com.sun.javaws.cache.DownloadProtocol.getDownloadSize(Unknown Source)
     at com.sun.javaws.LaunchDownload.downloadJarFiles(Unknown Source)
     at com.sun.javaws.LaunchDownload.downloadEagerorAll(Unknown Source)
     at com.sun.javaws.Launcher.downloadResources(Unknown Source)
     at com.sun.javaws.Launcher.handleApplicationDesc(Unknown Source)
     at com.sun.javaws.Launcher.handleLaunchFile(Unknown Source)
     at com.sun.javaws.Launcher.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)

Are you able to download your *.jar files directly from server
For example say,
http://127.0.0.1:8080/test/testme.jarIf yes,
Then problem should be with your *.jnlp file. Check all your *.jar with respect to context location of your url from where you are downloading *.jnlp file

Protect a jar file

how to protect a jar file so that no one can de -jar the class files from it
please suggest..
thanks..

Or alternatively they don't know why, and are too afraid to ask. I think a lot of these people only ask questions on forums, not of their colleagues or managers. Also they may be afraid of finding out because it will mean a discussion with a colleague or superior that again they're too afraid to have. They'd rather keep their heads down and deliver the wrong answer as instructed. Easy to be 'brave' on a forum, hiding behind a pseudonym, and easy to come up with solutions that way that make you look better than you really are. Not so easy to act like a professional.
I'm reminded of a former colleague who used to go around announcing he'd just 'realized' something after he had had a secret discussion with me. Didn't get him very far when I wasn't around.
Cultural things at work here too I suspect. Aussies and Americans and British don't mind arguing all day & laughing about it afterwards over a beer. Others' mileage seems to vary ;-)

Calling jar file from jsp - serious problem !

Hi there, I'm trying to call a jar from a jsp file. I need an import clause in my jsp, to the class I want to use.
I'm using eclipse, and while i"m writing "<%= " and the begining of my class name , he autocompletes it and automatically puts an import of my class in the top of the html. It is very convenient , but the problem is that he underling the class name (in the impot: <%@page import="myClass"%>), and I get "The import myClass cannot be resolved" error.
I got an advice to put my class in a package, since it was in a default package. I did it. But now I have 2 problems:
1. I can't run my jar in command window: java - jar myJar.jar. in gives me: Exception in thread "main" java.lang.NoClassDefFoundError....
2. I still get an error - "The import myClass cannot be resolved" in the jsp, although I threw the old jar (that his class I want to use was out of package), and brought a new jar after creating it.
I hope I managed to clarify myself. I'll be thankful of any help !!!

Hi MSoldier.
There are two ways to do this:
1) You use the java.lang.Runtime classes to start the java application in your JAR file, just like you would have done it from the command line. The Runtime class has three different exec() methods that can be used to run any program just like you would from the command line. Remember, using this method you will have to write everything just like if you run your Java application from the command line, incl. classpath etc. This way your Java application will be run as a separate process. When the application finishes the process is shutdown and the resources (RAM etc.) taken by it freed, just like when you shutdown any other application.
2) You can open the JAR file yourself from inside the JSP page, look inside the META-INF file to find the main class, and then calls the main class main method. There is an example of how to do this in the Java Tutorial available from Sun under the JAR files track. Check these links :
The Java Tutorial at Sun
http://java.sun.com/docs/books/tutorial/
The JAR File Tutorial at Sun
http://java.sun.com/docs/books/tutorial/jar/index.html
Opening JAR Files via the Java JAR File API
http://java.sun.com/docs/books/tutorial/jar/api/index.html
Note however, if you have just created some classes that you want to use from inside your JSP pages, and not a separate application that needs to be run separately, you should just include the JAR file with your custom classes inside the WEB-INF/lib directory. These classes are then automatically available to your JSP pages, just like the rest of the Java API.
I hope this answers your questions,
Kind Regards,
Jakob Jenkov
Software Architect
Jenkov Development
www.jenkov.com

How Can I protect my swf files from decompiling / saving

I have navigated through the internet for a long time now but
could not find the solution to my problem which is "how to protect
my swf file from decompiling/saving"?
I know that it CAN BE DONE and here is an example of a file
on the internet that cannot be saved or decompiled using any
software that I have come across (ie:SOTHINK decompiler, saveflash)
http://www.3dinternet.com/video.swf
Any help? any hints ?
Thanks
Hagop

Hagop,
> I have navigated through the internet for a long time
now but
> could not find the solution to my problem which is "how
to
> protect my swf file from decompiling/saving"?
There is no way to protect your SWF from decompiling. Any
commercial
software on the market can be decompiled -- including the
Flash authoring
tool and Photoshop, for example -- which is why softare
generally ships with
an end user license agreement (EULA) that expects you to
agree not to
decompile or reverse engineer your purchase.
Most Flash content (other than RTMP requests for video, for
example) are
HTTP requests, which by nature means the content is
downloaded to your hard
drive, just like HTML documents, CSS files, JPGs, and GIFs.
Your browser
requests the files, downloads them to your hard drive, then
displays them
from your local copy.
> I know that it CAN BE DONE and here is an example of a
> file on the internet that cannot be saved or decompiled
using
> any software that I have come across
What you've seen, then, is merely the result of software
that uses
unknown (to you or to your sofware) encryption/obfuscation
algorithms. Keep
trying, and you'll eventually nail it.
At best, you can use obfuscators to temporarily deter a
certain segment
of the decompiling-inclined population.
David Stiller
Adobe Community Expert
Dev blog,
http://www.quip.net/blog/
"Luck is the residue of good design."

How many Ways jar files from ear file on a jboss can be downloaded on clien

Aoa
How many Ways jar files from ear file on a jboss can be downloaded on client side
like jnlp etc..
Regards
M Fazal Ur Rehman

First, you need to be able to boot from the Recovery HD:
Boot Using Command+R keys:
1. Restart the computer.
2. Immediately after the chime press and hold down the
"COMMAND" and the "R" keys together.
3. Release the keys when the Utilities Menu appears.
Once at the Utilities Menu select Terminal from the Utilities menu in the screen's menubar. Now, you need to know where these new files are located. You move to any location using the 'cd' command such as cd /Users/user_name/Documents, then press RETURN. Replace user_name with your actual username. Next you need to do a directory listing to see if your files are in that location, Documents. Use ls -al to do a directory listing of the files and folders in Documents. If you find your new files there, then connect an external drive or flash drive. You will need to know the name you have assigned to this drive. It needs to be already formatted. Copy your files using cp /Documents/filename /Volumes/volname/filename. Replace volname and filename with those that apply. Press RETURN.
Or take it to your local Apple Store and see if they can do the chore for you.

Running jar files from the command line

I have always felt it would be useful to run a jar file from th command line in EXACTLY the same way as an EXE. On some systems, typing MYAPP.JAR will run the app, but doesn't output and command line data, so it only works for GUI apps. I've come up with a tiny C program that runs java -jar xxxx.jar for you.
#include <stdio.h>
#include <string.h>
#include <process.h>
void main(int argc,char *argv[])
     char cmd[1024];
     strcpy(cmd,"java -jar ");
     strcat(cmd,argv[0]);
     strcat(cmd,".jar");
     for(int arg=1;arg<argc;arg++)
          strcat(cmd," ");
          strcat(cmd,argv[arg]);
     system(cmd);
}Simply compile this to an exe, rename the exe to the name of your jar file and put it in the same directory. Then just type 'MyJarFile' (no jar extension) and it should run. It passes all command live args as well. Comments ?

Here's a better version. The JAR and the EXE can be anywhere in the PATH:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <process.h>
void main(int argc,char *argv[])
     char jar[1024];
     char cmd[1024];
     strcpy(cmd,argv[0]);
     strcat(cmd,".jar");
     _searchenv(cmd,"PATH",jar);
     strcpy(cmd,"java -jar ");
     strcat(cmd,jar);
     for(int arg=1;arg<argc;arg++)
          strcat(cmd," ");
          strcat(cmd,argv[arg]);
     system(cmd);
}

Protecting your jar file from been extracted

Similar Messages

Maybe you are looking for