Sunday, May 2, 2021

Re: GWT tutorial does not compile

At home (on my personal computer not employer workspace, without the restrictions of using only company repository),
I downloaded and ran your example using Broyer plugin. It works. Thank you. 
Then I tried the Ignacio Baca tutorial with maven (using IntelliJ Community Edition).
At step 3 Package, Run and Debug
I get an error

userr@DESKTOP MINGW64 ~/Documents/Learn/gwt/hello-app
$ mvn package
[INFO] Scanning for projects...
[ERROR] [ERROR] Some problems were encountered while processing the POMs:
[ERROR] Unknown packaging: gwt-app @ line 10, column 14
[ERROR] The build could not read 1 project -> [Help 1]
[ERROR]   The project me:hello-app:HEAD-SNAPSHOT (C:\Users\user\Documents\Learn\gwt\hello-app\pom.xml) has 1 error
[ERROR]     Unknown packaging: gwt-app @ line 10, column 14
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1]

Unfortunately, google groups strips out the xml formatting.

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="" xmlns:xsi=""


<!-- FIXME change it to the project's website -->



<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<!-- clean lifecycle, see -->

<!-- default lifecycle, jar packaging: see -->
<!-- site lifecycle, see -->

I will appreciate suggestions to fix this.
On Friday, April 30, 2021 at 3:15:58 PM UTC-5 wrote:
Forget something...

It's wise to separate the "client" and the "server" in two Maven projects. Don't use the example of the Mojo Maven plugin because it mixes the client and server on the same Maven project.

I've once used it mixed (see but at the end I had a lot of troubles with the classpath. 

Here is an example how you could separate the client and server. At the end your result on the client is JavaScript and you can copy the result to the server part using maven-dependency-plugin

Hope this helps. schrieb am Freitag, 30. April 2021 um 21:52:56 UTC+2:
... and yes, you can follow the tutorial with the TBroyer Maven plugin or the Mojo Maven plugin.

The code is the same, only the structure is different... You can compare both:
Lofi schrieb am Freitag, 30. April 2021 um 21:49:17 UTC+2:
I checked the old Maven GWT Plugin... ok it still works for GWT 2.9 but I won't use it anymore. 

If you have to use it here is an example - just the same demo from my example above but use the old Maven plugin:

The Java code is the same but it uses the structure of the old GWT Maven plugin... just take a look at the README of the project above.

Hope this helps.
likejudo schrieb am Freitag, 30. April 2021 um 20:27:00 UTC+2:
Mojo GWT Maven plugin packages as war.
if I package as war, can I still follow the tutorial?

On Friday, April 30, 2021 at 12:17:13 PM UTC-5 likejudo wrote:
  I don't have a choice. I have to use what is in my employer's repository. Mojo GWT Maven plugin 2.90 is in the repo.  

On Friday, April 30, 2021 at 12:09:28 PM UTC-5 wrote:
You can use my zip file and follow the tutorial using that zip file Maven project... 

The GWT Java code like in the tutorial doesn't change at all, only the project structure with TBroyer GWT Maven plugin... schrieb am Freitag, 30. April 2021 um 19:07:22 UTC+2:
Do not use that old GWT Maven plugin... it makes no sense, it is too old and all of the new stuffs in GWT are using TBroyer GWT Maven plugin 😉

It's very good Maven plugin...

likejudo schrieb am Freitag, 30. April 2021 um 18:51:52 UTC+2:
I was trying to follow the tutorial so I did not try your other sample yet.
I think the reason is, my employer uses Mojo GWT Maven from Codehaus.
Unless I am mistaken, it does not seem to have gwt-app packaging.

On Friday, April 30, 2021 at 11:46:04 AM UTC-5 wrote:
Hmm wyrd...

Did you try to download the zip (, unpack it and start in the unpack directory?

mvn gwt:generate-module gwt:devmode

or complete:

mvn net.ltgt.gwt.maven:gwt-maven-plugin:generate-module net.ltgt.gwt.maven:gwt-maven-plugin:devmode
likejudo schrieb am Freitag, 30. April 2021 um 17:54:19 UTC+2:
> Try following this tutorial
I tried it but when I run mvn package
I get error:
Unknown packaging: gwt-app

On Thursday, April 29, 2021 at 3:39:14 PM UTC-5 wrote:
Try following this tutorial

On Thursday, April 29, 2021 at 11:36:02 PM UTC+3 wrote:

today I won't use the GWT plugin for Eclipse anymore... 

I would just use Eclipse / IntelliJ / Visual Studio Code and Maven.

Some introductions:
Hope this helps.
likejudo schrieb am Donnerstag, 29. April 2021 um 19:57:18 UTC+2:
I am learning GWT and was trying to run this tutorial

Using the Eclipse GWT plugin 3.0 on Windows 10 and JDK 11

I get this error on the first line Error: There is '1' error in 'gwt-module.dtd'.

I installed the plugin from the marketplace.
I see this error in other tutorials too.

Any suggestions appreciated.

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