Encoding problem in Vaadin 8 Framework application when building with Gradle in Windows

Question

When you use the Gradle plugin com.devsoap.plugin.vaadin for building Vaadin 8 applications everything works fine as long as you use Linux or Mac. setContent(new Label("A B C Å Ä Ö")) prints out the characters A B C Å Ä Ö as expected.

However, if you run the application in Windows the following characters are printed out: A B C Å Ä Ö.

How can I fix the problem?

See below the essential files in a sample project.

build.gradle

plugins {
  id 'com.devsoap.plugin.vaadin' version '2.0.0.beta2'
}

ExampleUI.java

@SuppressWarnings("serial")
public class ExampleUI extends UI { 
    @Override
    protected void init(VaadinRequest request) {
        setContent(new Label("A B C Å Ä Ö"));
    }
}

ExampleServlet.java

@WebServlet(
    asyncSupported=false,
    urlPatterns={"/*","/VAADIN/*"},
    initParams={
        @WebInitParam(name="ui", value="haba713.ExampleUI")
    })
public class ExampleServlet extends VaadinServlet {
    private static final long serialVersionUID = 1L;
}

Environment

• Windows 10 Pro, version 20H2, OS build 19042.985
• OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.282-b08, mixed mode)
• Gradle 5.6.4
• com.devsoap.plugin.vaadin version 2.0.0.beta2

Answer 1

The java sources on Linux and Mac are UTF-8 by the default encoding (editor), and evidently also compiled by UTF-8 (compiler).

On Windows with unchanged sources in the editor Å Ä Ö would be seen as weird character pairs. If the editor is explicitly set to UTF-8 they are shown correctly.

But evidently the compiler uses the default platform encoding, yielding those pairs.

So set the gradle compiler encoding.

compileJava {
    options.encoding = 'UTF-8'
}

(Not much experience with gradle.)

As the IDE often shadows the build process of gradle, also set the editor/compiler encoding to UTF-8.