Skip to content

Trouble Shooting Guide

This guide helps you to identify potential root causes for problems that you encounter during modeling and code generation. The root causes that are listed and explained here are not specific to a certain generator.

Error Code 409 (Conflict)

The error message looks like this:

Der Generator hat einen Fehler gemeldet: Server respond unexpected
error code 409, Conflict

Known reasons for this problem are:

  • Your model contains two elements of same type and with the same name, e.g. two UI components with the same name. This then leads to a duplicate developer area ID: While transform the new target, a problem with a developer area occurred: Found a new developer area with ID '.... Get rid of the duplicate model element to solve that problem, e.g. rename one of them.
  • At least one of the model files uses “Byte Order Mark” (BOM). The error message doesn’t tell this detail but the following: Der Cloud service hat einen Fehler aufgezeichnet. Dieser Fehler wird dem Hersteller des genutzten Generators in anonymisierter Form zur Verfügung gestellt. Weder Informationen über Sie noch über Ihr Modell werden dem Hersteller übermittelt.. Please check your input model files to find out whether they use BOM. You can do this by right-clicking a model file and opening the “Properties” dialog. You can get rid of the BOM by temporarily changing the file encoding to a non-UTF one, removing the first three bytes and then changing the encoding back to UTF-8.

Apart from that, sending an email to describing your problem is your best bet.

Problems with Developer Areas

You can get problems with developer areas when the commented code lines, e.g. //DA-START..., //DA-ELSE... and //DA-END... are corrupted or incomplete.

Incomplete or nested Developer Area

Virtual Developer finds incomplete or nested comments that together normally should represent a developer area (e.g. a missing //DA-END...). The error message looks like this:

src/main/java/ While parsing the modified content from the file
sent by the user, a problem with a developer area occurred: Found a
new developer area start with ID ‘...' at position 35956 in line 786,
but there is already a developer area open with ID '...' at position 35595.
Recursive developer areas are not permitted


Remove the erroneous comments, regenerate and possibly re-add manually modified code.

Unused Developer Area (unknown ID)

Virtual Developer finds a modified developer area with an id that is not used anymore in a generated file. The error message looks like this:

Found an unused developer '...' area in the previous target content.


Remove the erroneous developer area, regenerate and possibly re-add manually modified code.

Same File generated by two different Generators

If two different generators try to write the same file, the cloud connector will show this as an error in the Eclipse problem view and marker view. The error message looks like this:

Die Datei '...' wurde vom Generator '...' geschrieben und würde nun von
Generator '...' erneut übergeschrieben  ... Diese Datei wird von
mehr als einem Generator beschrieben

You might be able to solve the problem by assigning a virtual project to a different Eclipse project in the workspace. However, this problem could also point to a bug in one or more generators since having two identical source code files would normally not make sense even if they are in two different locations.

Mutated Vowels (Umlaute) not generated properly

The file encoding of your Eclipse and your input model files has to be UTF-8. If this is not the case, mutated vowels in model files will not be written correctly to generated files.

Check the file encoding of your Eclipse (eclipse.ini), of your Eclipse workspace and of your model files. You can set the file encoding for Eclipse by setting -Dfile.encoding=UTF-8 in the eclipse.ini file. The default file encoding for your Eclipse workspace can be set in the Eclipse preferences (“Window” -> “Preferences”) in the section “General” -> “Workspace”.

Model edited in Text-Editor, generated Files not changed

Model files have to be visible to Eclipse (and thus the Virtual Developer Cloud Connector). Otherwise they cannot be sent to a generator. When you edit a model file with an external editor, Eclipse does not instantly know about this since it has an internal caching mechanism for files. Refresh the Eclipse project that contains the model files and try to run the generation again.

Generation is “green”, but not all Files generated

It is possible that the colors in the project configuration view are all green, but still there are not all file successfully generated. In this case you can find an error marker attached to a to-be-generated file. As usually, the error marker is visible in several places in Eclipse, e.g. in Package Explorer, Project Explorer, Markers, and Problems view.

If you find such problems, it is either a generator bug or the original content of the to-be-generated file is somehow corrupt. You can verify the latter case by renaming the original file, re-run the generation and, if successful, diff the new result with the older, renamed file.

Virtual Developer Beginners Settings

If the above is not the case, you should check your Virtual Developer Cloud Connector settings (“Windows” -> “Preference”, “Virtual Developer” -> “Generation”). There you find two check boxes. If one or two of them are checked, this could be the reason for your generation run not having overwritten existing files.

Project Configuration View shows “no model selected”

In a generation project you can assign model files to the generation project as well as to individual generators. When you assign model files to the generation project, which is common practice, the individual generators still show “no model selected”. This is not a mistake and not a problem.

Error in /in-memory-model …

You have assigned model files and run the generator(s). The generation fails and the generator shows one or more error message like this:

Error in /in-memory-model ...
Error in /in-memory-model ...

This means the input model is incomplete. The error messages give you more information about the model files that still have to be assigned to a generation project.

Transitive Dependencies of Model Files

If you assign more model files and the additional model files themselves have references to even more model files, you could see errors in subsequent generation runs that you haven’t seen before.

Other Errors

If a generator has an internal error and the error message or the trouble shoot guide doesn’t help you to solve the problem, send an email to describing your problem. We will take care of this.