Technical Support


Jar2Exe can run in Wizard mode and Command line mode.

Get detailed usage of Wizard mode, command line mode and generated binary files.


Parameters can be configured to generated binary executive, such as Java VM parameters, system properties etc.

This is the descriptions of configurations, including overview introductions and detailed syntax.

Integrate API

To integrate with generated exe is not necessary. But if you want to let some of the enhanced functions to work, you need to do a little of integration. Every api to integrate is very simple.

This is the introduction and usages of API.


You can learn to use Jar2Exe by referring to the demo programs.

Solution advices

Typical usage of Jar2Exe with detailed steps and live demos in practice.

Such as console tool, desktop window, background service, webapp etc.




After purchased, you need to activate Jar2Exe before you use Jar2Exe to generate exe files for redistributing. Activated Jar2Exe will authorize generated exe to run as a product.

This is to tell you how to activate.


Typical questions asked by Jar2Exe users.



OpenJDK 15 Support

Does Jar2Exe suppport JDK 15+ ??? We are using Open JDK 16 to develope out apps. 


Hi Team

We are using purchased version of Jar2Exe. We have enabled encryption for the jar. Can you share some data related to type of encryption used and how secure is jar after encryption?


V2.2:  the encryption is :   filename hash  +  jar file encryption

V2.5:  filename hash + 2 times of file encryption

When program runs, no temp file will be written.  The decryption is in memory.


Tq for the response. We are using v2.5. Please provide us more details on below.

1. Type of encryption used(AES/RSA/other)

2. key formation 

3. please elaborate - filename hash + 2 times of file encryption

Use Jar2Exe with VMProtect

Hello, can I use my Jar2Exe executable with VMProtect? Are there any extra steps I need to take to make it work?

Failed to Convert to .EXE


I have been using .exe app from 3 years, recenlty after updating to V2.5 unable to convert to exe, I'm using same jar file which converted successfully in previous version of .exe.

Please help me, I'm  stuck in middle.


Lost drag and drop


I have a java app that uses drag and drop function, the jar file run correctly but after convert to exe using jar2exe drag and drop functionalities now missing, any solution?

Which OS?

Thank you for your message.

Which OS? Could you send me a demo java program to show "drap and drop"?

Jar2exe close emergency

Hello I've perchese your software years ago it to generate exe. But my software has been haecked I was asking is there a way to track and code the exe files . So is been able to open as of it was a trail version of yours??
If possible let me know and cost involved.


BCEL error

I created an executable from war with the last version (2.2.4), the creation is done without error messages. But executing the exe file a message is showed and no service is started.

The Error is:

Exception in thread "main" org.apache.tomcat.util.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 18
        at org.apache.tomcat.util.bcel.classfile.Constant.readConstant(
        at org.apache.tomcat.util.bcel.classfile.ConstantPool....

The exe file uses apache tomcat 7.0.8

Which version of Java are supported?

Java must be 32 or 64 bits?




Some framework may be not compatible with encryption

When encrypted, it is not allowed to get content of ".class" file by getResource. But some framework will try to load .class and do more by themselves, such as spring. 

So, we could choose to partially encrypt our program, and let those class which need to be loaded, not encrypted.

Standard License

Hi, I have a question for Standard license.

Once I buy the product, how many users are allowed to use in our company?


For Standard License, the number of PC is unlimited in a company.


Hi, I'm using jxbrowser and it doesn't allow me to convert jar to exe anymore, it just stuck and crash!

UTF8 default font issue


When I am using jar file wrapped into your executable - it ignores file.encoding=UTF8 JVM property in Config Internal and writes junk characters into a file.

When the same jar file is used directly : java -jar -Dfile.encoding=UTF8..  jar.jar - it works fine.


Could you please advise.


Thank you

Mac Executable


I tried to make executable for MAC, but it doesn't work.

Please help me on this

Mac Excutable

Thanks for reply, Yes i did 64 bit executable, but i don't understand 2 point. Please explain steps to make MAC executable and running on MAC

Need to `chmod +x` when copied to mac

On Linux and Mac, executive files need to have execute privilege to run. Right now, Jar2Exe can run on Windows only, but FAT32 or NTFS could not express the `execute privilege`. So, after generated exe file is copied to Mac, we need to use `chmod +x (binary file)` to add execute privilege to let it runnable.

Generating for Mac ok but when I codesign the executable


I'm using Jar2Exe fine in most cases but have hit a slight problem when generating for "mac" and applying codesigning to the executable.

to codesign I run

          codesign -s "MyCompanyID" ./MyAppExecutable

But when I run this I get

$ ./MyAppExecutable

Error occurred during initialization of VM
java.lang.Error: java.lang.ClassNotFoundException: com.regexlab.j2e.Jar2ExeClassLoader
           at java.lang.ClassLoader.initSystemClassLoader(
           at java.lang.ClassLoader.getSystemClassLoader(
Caused by: java.lang.ClassNotFoundException: com.regexlab.j2e.Jar2ExeClassLoader
           at java.lang.ClassLoader.loadClass(
           at sun.misc.Launcher$AppClassLoader.loadClass(
           at java.lang.ClassLoader.loadClass(
           at java.lang.Class.forName0(Native Method)
           at java.lang.Class.forName(
           at Method)
           at java.lang.ClassLoader.initSystemClassLoader(
           at java.lang.ClassLoader.getSystemClassLoader(

I have  "/checksum:false" set already BTW.

Is there a way round this ?  I'm sensing there is some overlap in how Jar2Exe and codesign define the executable header info.






64-bit service EXE not working

Bought JAR2EXE recently and I cannot get it to work...

I am trying make a 64-bit service application.
I thought that Jar2EXE would find JRE automatically but the EXE file built always fails with either Java Runtime Environment not valid or Java Runtime Environment not valid.

However, java binary is found just fine:

c:\Users\Bruger\Desktop>java -version
java version "1.8.0_181"
Java(TM) SE Runtime Environment (build 1.8.0_181-b13)
Java HotSpot(TM) Client VM (build 25.181-b13, mixed mode, sharing)

Since I am planning on searching for (and installing the JRE itself if missing) in my application's setup, please show me a configuration that can either always find the installed JRE or alternatively, please tell me exactly which files from the JRE directories that need to be placed relative to the service binary's directory in order for the JRE to be found ??

Thank you in advance


64 bit exe could only run with 64 bit JRE

On 64 bit Windows, 32 or 64 bit of JRE can run. Both 32 and 64 can be installed together.

Your "java -version" shows that, your JRE is not 64 bit edition.

Jar2Exe doesn't recognize the main jar file

Tried the helloworld and it worked using the command line.

I then moved the jar and class files of the program to be exe'ed to the root directory (c:\) and successfully compiled the files and program. Thank you.

It seems that the directory where I currently have the files no longer is acceptable to Jar2Exe program. That was the cause of the Jar2Exe program not recognizing the main jar. Seems that Jar2Exe relies on Windows to locate the files where the "previously" compiled jar and class files resided. When the PC "user" location naming was changed,  Jar2Exe still looked for it in the directory under the older user. Probably a Windows created problem of providing the Jar2Exe program wrong location info.

I Cant Activate anymore

I order jar2exe in 2016 and know i can activate anymore, can you helpe me ? 

Warning Message "Java Runtime

Warning Message "Java Runtime Environment not found" is shown after trying to run generated EXE!

Not run app after signing "Code signing certificate"

Currently, I use trial version, and after I sign the exe file using "Code signing certificate", the app don't run and show error message: "the exe cannot be modified after it generated". Please help me to solve this issue.

If I purchase "Personal Base License", can this issue be resolved?


Is there other payment, not Paypal?

I want to purchase Personal License. Is there other payment, not Paypal? For example, Visa Card or Crypto Currency?

Because my paypal account has limited.

Unable to Generate Key

Dear Support Team;


I am unable to generate my laptop key. kindly help in this regard.


my username is msibtain and purchase jar2exe personal version.


Kindly help in this regard.

type Exception report


description The server encountered an internal error () that prevented it from fulfilling this request.


org.apache.jasper.JasperException: javax.servlet.ServletException: java.lang.NoClassDefFoundError: Could not initialize class com.regexlab.product.KeygenTools

root cause

javax.servlet.ServletException: java.lang.NoClassDefFoundError: Could not initialize class com.regexlab.product.KeygenTools

root cause

java.lang.NoClassDefFoundError: Could not initialize class com.regexlab.product.KeygenTools

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.26 logs.
Apache Tomcat/6.0.26

Jar2Exe Personal

Improve for personal Jar2Exe and I have not yet received the change

Activación de la licencia

Hola buenas tardes, alguien que me pueda colaborar no he podido realizar la activacion de la licencia comprada la orden de compra es 



De antemano gracias por la atencion prestada y por una pronta solucion


Extend trial

I sent an email requesting to extend the trial. I was told to create a new account, so I did. I get an email for one time login, I sign in. I then have a choice to send a password to my email but entering a captcha continually fails with the following message.... I guess I can't paste the message here.. It says session reuse attack detected. The answer you entered for CAPTCHA is not correct. I have tried using IE, OPERA, and Firefox. This is getting very frustrating in order to extend a trial for a product that I am interested in.




mac, linux not working

i had licensed 


but linux, mac file not working 


execute-> notting happend


please help 



Please `chmod +x yourbinaryfile` before run

Because the windows filesystem could not express the "execute" privilege, after you copy your generated binary file to Linux and Mac, please `chmod +x yourbinaryfile` first.

In the future release I'm thinking to generated a ".zip" file instead to contain the "execute" privilege.

Parameter /checksum:false doesn't work?

May you check command line parameter: /checksum:false 

It didn't work for me. But, it works well if I use GUI in j2ewiz.exe

I used available on your site version


This is very important for me, because I would like to use code signing for my EXE-file. 


I tried a trial version to convert jar to exe with encryption but my application didn't work properly and as I tried without encryption it works properly.. Pls give me any suggestions so that I can purchase license....

Which type and options have

Which type and options have you checked? You contact me directly by email:

The "checksum:false" can only be use after activated. Please make sure you are on the pc activated.



Yes. You are right. I just used jar2exe in a trial mode. (another window account was involved) 

Now it works fine! 




Java runtime not valid

I've just downloaded a demo version and tried building an .exe. The wizard seemed simple enough to use although it surprised me I never had to specify where the jre I'd like to use is. When I execute the .exe however I get the following error message:

C:\Program Files\Java\jdk1.8.0_91/jre\bin\server/jvm.dll is not a valid Win32 application.

Java Runtime Environment not valid.

EXE crashing when using Hide or Encrypt option

I am creating a java APP and uging jar2exe to distribuite it as a exe file.

I have the following issue: when using the "Hide class files" or "Encrypt and hide class files" option my application craches when opening a certain JFrame for the second time. In other words:

1. I open my application: OK

2. I open a certain form to input some data: OK

3. I reopen the same form to input other data: crashes

Using other forms it is OK, I do not know what to look for.

If I use the original .jar or I do not use Hide or Encrypt option it works fine. 

Here is the generated error file:

What can I do?





Java Runtime Environment not found


I have the Java SDK installed. When I start the .exe generated by jar2exe, I get the error message: "Java Runtime Environment not found.".  So I installed the latest JRE, and I still get this error message.

May you please advise ?





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