Binding elements/types to Java classes
if there is jbxb:class, an element is bound to the specified Java class
if there is jbxb:mapEntry and attribute impl is specified, an element is bound to the specified Java class. If attribute impl is not specified, a special class is used internally by the framework to represent a map entry
otherwise, an element is bound to a Java class following the default binding rules
Note, jbxb:class and jbxb:mapEntry are mutually exclusive and MUST NOT be used together for the same type or element. Doing this will result in a binding exception. But, since, elements inherit binding metadata from its types and override them, it's legal to annotated a type with jbxb:mapEntry and an element of this type with jbxb:class. In this case, an element is NOT bound as a map entry but just to Java class.