Error compiling vaadin widgets

When running vaadin plugin to compile widget set we see:

:vaadinCompile
Errors in ‘jar:file:/Users/user/.gradle/caches/modules-2/files-2.1/com.google.gwt/gwt-user/2.8.2/a2b9be2c996a658c4e009ba652a9c6a81c88a797/gwt-user-2.8.2.jar!/com/google/gwt/validation/client/impl/PropertyDescriptorImpl.java’
Line 31: The type PropertyDescriptorImpl must implement the inherited abstract method CascadableDescriptor.getGroupConversions()
Errors in ‘jar:file:/Users/user/.gradle/caches/modules-2/files-2.1/com.google.gwt/gwt-user/2.8.2/a2b9be2c996a658c4e009ba652a9c6a81c88a797/gwt-user-2.8.2.jar!/com/google/gwt/validation/client/impl/ConstraintDescriptorImpl.java’
Line 35: The type ConstraintDescriptorImpl must implement the inherited abstract method ConstraintDescriptor.getMessageTemplate()
Line 35: The type ConstraintDescriptorImpl must implement the inherited abstract method ConstraintDescriptor.getValidationAppliesTo()
Errors in ‘jar:file:/Users/user/.gradle/caches/modules-2/files-2.1/com.google.gwt/gwt-user/2.8.2/a2b9be2c996a658c4e009ba652a9c6a81c88a797/gwt-user-2.8.2.jar!/com/google/gwt/emul/java/lang/String.java’
Line 31: The import javax.annotation.Nonnull cannot be resolved
Line 193: Nonnull cannot be resolved to a type

Error looks to be missing dep

[INFO]
Compiling module com.celertech.riskmonitor.AppWidgetset
[INFO]
Tracing compile failure path for type ‘javax.validation.ParameterNameProvider’
[ERROR]
Errors in ‘jar:file:/Users/user/.gradle/caches/modules-2/files-2.1/javax.validation/validation-api/1.1.0.Final/7d49b53caed9bd81d172807c3e096d24f3c57090/validation-api-1.1.0.Final-sources.jar!/javax/validation/ParameterNameProvider.java’
[ERROR]
Line 54: No source code is available for type java.lang.reflect.Method; did you forget to inherit a required module?
[ERROR]
Line 44: No source code is available for type java.lang.reflect.Constructor; did you forget to inherit a required module?
[INFO]
Tracing compile failure path for type ‘com.google.gwt.validation.client.impl.ConstraintDescriptorImpl’

plugins {
id ‘java’
id ‘eclipse’
id ‘com.jfrog.artifactory’ version ‘3.0.1’
id ‘fi.jasoft.plugin.vaadin.groovy’ version ‘1.1.6’
}

ext {
vaadinVersion = ‘8.1.0’
}

You are using a very old gradle vaadin plugin version, you might want to update to

'com.devsoap.plugin.vaadin' version '1.3.0'

Also, I noticed that you are using the groovy version of the plugin. A while back the groovy/java versions were merged into one plugin so now there is only one plugin that handles Java, Groovy and Kotlin.

If you indeed are creating a Vaadin application using Groovy then you will need to add the groovy plugin so the groovy sources are compiled. Have a look at
https://github.com/johndevs/gradle-vaadin-plugin/wiki/Creating-a-Groovy-Project
for help. You don’t need the groovy plugin if your application is written in Java.

I still see this

Task :compileJava
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

Errors in ‘jar:file:/Users/user/.gradle/caches/modules-2/files-2.1/com.google.gwt/gwt-user/2.8.2/a2b9be2c996a658c4e009ba652a9c6a81c88a797/gwt-user-2.8.2.jar!/com/google/gwt/validation/client/impl/PropertyDescriptorImpl.java’
Line 31: The type PropertyDescriptorImpl must implement the inherited abstract method CascadableDescriptor.getGroupConversions()
Errors in ‘jar:file:/Users/user/.gradle/caches/modules-2/files-2.1/com.google.gwt/gwt-user/2.8.2/a2b9be2c996a658c4e009ba652a9c6a81c88a797/gwt-user-2.8.2.jar!/com/google/gwt/validation/client/impl/ConstraintDescriptorImpl.java’
Line 35: The type ConstraintDescriptorImpl must implement the inherited abstract method ConstraintDescriptor.getMessageTemplate()
Line 35: The type ConstraintDescriptorImpl must implement the inherited abstract method ConstraintDescriptor.getValidationAppliesTo()
Tracing compile failure path for type ‘javax.validation.ParameterNameProvider’
Errors in ‘jar:file:/Users/user/.gradle/caches/modules-2/files-2.1/javax.validation/validation-api/1.1.0.Final/7d49b53caed9bd81d172807c3e096d24f3c57090/validation-api-1.1.0.Final-sources.jar!/javax/validation/ParameterNameProvider.java’
Line 54: No source code is available for type java.lang.reflect.Method; did you forget to inherit a required module?
Line 44: No source code is available for type java.lang.reflect.Constructor; did you forget to inherit a required module?
Tracing compile failure path for type ‘javax.validation.executable.ExecutableValidator’
Errors in ‘jar:file:/Users/user/.gradle/caches/modules-2/files-2.1/javax.validation/validation-api/1.1.0.Final/7d49b53caed9bd81d172807c3e096d24f3c57090/validation-api-1.1.0.Final-sources.jar!/javax/validation/executable/ExecutableValidator.java’
Line 53: No source code is available for type java.lang.reflect.Method; did you forget to inherit a required module?
Line 94: No source code is available for type java.lang.reflect.Constructor; did you forget to inherit a required module?
Tracing compile failure path for type ‘com.google.gwt.validation.client.impl.ConstraintValidatorContextImpl’