As an experiment I removed an old exclusion of com.google.gwt:gwt-dev that some job-ancestor of mine had specified (see the commented part in my pom.xml snippet below):
...
<!-- MVP component -->
<dependency>
<groupId>com.gwtplatform</groupId>
<artifactId>gwtp-mvp-client</artifactId>
<version>1.6</version>
<!--
<exclusions>
<exclusion>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-dev</artifactId>
</exclusion>
</exclusions>
-->
</dependency>
...
and now I don't get the mentioned compiler error anymore but instead I end in the same odd
'Throwable.HasJavaThrowable' has invalid name '?'
exception that I describe in my other thread. So, both, project migrations are now stuck in the same issue ...
:-(