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New service works fine in debug mode bu throws error when deployed

Backendless Version (3.x / 5.x, Online / Managed / Pro )

v6.1.7, Online

Client SDK (REST / Android / Objective-C / Swift / JS )


Application ID


Expected Behavior

Created a new service in Java for QR code generation (“QRgen”). Service takes in a string, and dimensions (pixels) of the desired output. It has 2 methods. One of them returns a bytestream and another returns a png file and creates an entry in table qr_code.

Please describe the expected behavior of the issue, starting from the first action.

  1. I downloaded the java SDK and I built the class(“QRgen”) offline using intellij IDEA.
  2. I ran to test it in debug mode. Both methods worked fine.
  3. I ran and the service was seen on Backendless as a Deployed Service.
  4. I invoked the deployed service in curl. Was expecting to see the same results as in debug mode.

Actual Behavior

When running the service QRgen in deployed mode, I see the following error when either of the 2 methods is invoked:

  • 400 - Type:“java.lang.NoClassDefFoundError”, Description:“Could not initialize class”, ExceptionClass:“ServiceException” {Msg:“none”, Cause:“none”}

Reproducible Test Case

Go to the app’s Business Services. Click on QRgen. Select either of the 2 POST methods. Pass these parameters and invoke.

“data”: “abcde”,
“width”: 200,
“height”: 200

Could you please zip up your project, upload the zip to the Backendless files storage and send us the link for it? You can email the link to


That link will not work, it is a link that works only for you. To get a public link, click the link icon for the file.

And this is thr recipe I followed.

1 Like

Where did you put your code?

Hi there, any update on this issue. Planning to go live next week.

Hello @Sanjay_Iyer

Unfortunately, there is no code in the archive to deploy. Could you send us an archive to help reproduce the problem?


It is under src/com/intrceptx/models.

I had responded to this request long ago, by email. Guess I will have to come to this page to respond? Lesson learnt :slight_smile:


I apologize for the current situation. I downloaded the archive from the link that you attached in this topic and the “models” folder is empty.

Could you please try this?


We were able to reproduce your problem.
The internal ticket BKNDLSS-23321 is created, we will let you know about solution.


Hello @Sanjay_Iyer

We made a fix.
Please check if it works for you.
Please write about the result.

It worked. Thanks a lot.