Design-Time XML Validation
All XML documents that have a schema or a DTD registered with JDeveloper (such as page definition files, .cpx files, page definition files, faces configuration files, web.xml, and so on) provide validation as well as code insight.
When you create Web pages and work with the ADF data controls to create the ADF binding definitions in JDeveloper, the Oracle ADF declarative files you edit must conform to the XML schema defined by Oracle ADF. When an XML syntax error occurs, the JDeveloper XML compiler immediately displays the error in the Structure window. You can double-click the error to open the file in the XML editor.