Embedding an advanced XML editor based on XXE in your Java™ application is pretty easy.
This XML editor could be a simple, single document, single view, XML editor or a more elaborate, multi-document, possibly multiple views per document, XML editor similar to the desktop application. It's equally as easy to embed the equivalent of the full desktop application in your Java application.
In all cases, note that you may embed a stock XML editor or on the contrary, a heavily customized/extended one. The XML editor you'll embed is really XMLmind XML Editor and not a simplified version. As such, it supports exactly the same customizations/extension points as the desktop application. In fact, you'll have to develop and test your customizations/extensions using the desktop application before embedding them in your own application.
In order to embed an XML editor in your application, the first step is to create a single, self-contained
xxe.jar files containing everything needed to run XXE. This is done using the deployxxe command-line tool.
This first step as well as all the other steps are explained in XMLmind XML Editor - Developer's Guide.