[FIXED] Updating Vaadin project's GWT for Java 11

Issue

I'm unable to build my maven project with vaadin and gwt components with JDK 11.

I've updated the gwt-user and gwt-dev to latest (2.8.2) version.

I'm using Vaadin7, tried with Vaadin8 also. Try to compile with the vaadin-maven-plugin.

The output of my maven build :

[ERROR] Hint: Check that your module inherits 'com.google.gwt.core.Core' either directly or indirectly (most often by inheriting module 'com.google.gwt.user.User')

I saw related questions but nothing working for me.

Can this stack work with Java 11 ? It works up to Java 8.

EDIT : To compile with JDK11, you'll need gwt-user, gwt-dev and vaadin-maven-plugin to 2.8.2. Then you'll need to upgrade Vaadin to Vaadin 8.9.1.

Solution

Updating the GWT dependencies to 2.8.2 is not enough. You also need to use a version of vaadin-maven-plugin that is based on GWT 2.8.2. I don't remember exactly which version number was the first one that works, but I have personally had errors with Vaadin 8.0 whereas everything has worked for me with Vaadin 8.8.

Answered By - Leif Åstrand
Answer Checked By - Gilberto Lyons (JavaFixing Admin)