I am asked to update some features in existing GWT&EXT based project, which in the production with following jars. I only have access to the latest GWT SDK, which I am using to compile those jars.

GWT jars: gwt-crypto-1.0.3.jar, gwt-hashcode-equals-0.1.0jar, gwt-incubator-security-1.0.1-SNAPSHOT.jar, gwt-servlet.jar, gwt-sl-1.0.jar gwtupload-0.6.1.jar

EXT jar: gxt-2.2.5-gwt2.jar

GWT SDK: google eclipse plugin 4.4 and 4.6

Eclipse Version: luna and neon.

I am getting following error and need your assistant to resolve to move on.

racing compile failure path for type 'com.extjs.gxt.ui.client.widget.form.HtmlEditor'
[ERROR] Errors in 'jar:file:/C:/Users/xxx/Documents/xxx/WebContent/WEB-INF/lib/gxt-2.2.5-gwt2.jar!/com/extjs/gxt/ui/client/widget/form/HtmlEditor.java'
[ERROR] Line 548: Type mismatch: cannot convert from com.google.gwt.dom.client.Element to com.google.gwt.user.client.Element
[ERROR] Hint: Check the inheritance chain from your module; it may not be inheriting a required module or a module may not be adding its source path entries properly
[ERROR] An internal compiler exception occurred

Caused by: java.lang.IncompatibleClassChangeError: Found interface com.google.gwt.core.ext.typeinfo.JClassType, but class was expected
at com.extjs.gxt.ui.rebind.core.TemplatesGenerator$SourceGenerator.validateType(TemplatesGenerator.java:142)