Error:GWT Compiler: No source code is available for type com.fasterxml.jackson.annotation.JsonTypeInfo.As; did you forget to inherit a required module?

[dynamphorousnmt]

I'm trying a very simple example just testing creating an ObjectMapper for or a very simple class object with only primitive types (ints & Strings). and I'm getting lots of errors during compile. My GWT version is 2.8.2

Information:javac 10.0.2 was used to compile java sources
Information:2/5/2019 9:09 PM - Compilation completed with 11 errors and 4 warnings in 46 s 14 ms
Error:GWT Compiler: com.github.nmorel.gwtjackson.client.ObjectMapper cannot be resolved to a type
Error:GWT Compiler: com.github.nmorel.gwtjackson.client.ObjectWriter cannot be resolved to a type
Error:GWT Compiler: com.github.nmorel.gwtjackson.client.JsonSerializationContext cannot be resolved to a type
Error:GWT Compiler: com.github.nmorel.gwtjackson.client.ser.bean.ObjectIdSerializer cannot be resolved to a type
Error:GWT Compiler: com.github.nmorel.gwtjackson.client.JsonSerializer cannot be resolved to a type
Error:GWT Compiler: com.github.nmorel.gwtjackson.client.JsonSerializerParameters cannot be resolved to a type
Error:GWT Compiler: com.github.nmorel.gwtjackson.client.ser.bean.TypeSerializationInfo cannot be resolved to a type
Error:GWT Compiler: No source code is available for type com.fasterxml.jackson.annotation.JsonTypeInfo.As; did you forget to inherit a required module?
Error:GWT Compiler: client.data.itemInventory cannot be resolved to a type
Error:GWT Compiler: client.data.itemListMapper cannot be resolved to a type
Warning:GWT Compiler: Unknown type 'com.github.nmorel.gwtjackson.client.JsonSerializationContext.Builder' specified in deferred binding rule
Warning:GWT Compiler: Unknown type 'com.github.nmorel.gwtjackson.client.ObjectWriter' specified in deferred binding rule

I've looked through the errors others have had, and nothing is jumping out at me as being wrong. These are the inherits in my gwt.xml file

<inherits name='com.google.gwt.user.User'/>
<inherits name='com.google.common.base.Base'/>
<inherits name='com.google.common.collect.Collect'/>
<inherits name='com.google.gwt.json.JSON'/>
<inherits name='org.moxieapps.gwt.highcharts.Highcharts'/>
<inherits name='com.github.gwtd3.D3'/>
<inherits name='com.google.gwt.webworker.WebWorker' />
<inherits name='com.github.nmorel.gwtjackson.GwtJackson' />

And maven included the jar files:

gwt-jackson-0.15.4.jar
jackson-annotations-2.9.6.jar
jackson-annotations-2.9.6-sources.jar
javapoet-1.0.0.jar

I am using Guava, but I'm not trying to serialize any guava objects yet.... Got any ideas?