JAXB is the default data binding for CXF. If you don't specify one of the other data bindings in your Spring configuration or through the API, you will get JAXB. Releases of CXF since 2.3.x have used the JDK7 default of JAXB 2.2, however Maven users running on JDK 6 will need to use the Java endorsed override mechanism to use JAXB 2.2 instead of JAXB 2.1.
JAXB uses Java annotation combined with files found on the classpath to build the mapping between XML and Java. JAXB supports both code-first and schema-first programming. Schema-first supports the ability to create a client proxy, dynamically, at runtime. See the CXF DynamicClientFactory class.
CXF uses the JAXB reference implementation. To learn more about annotating your classes or how to generate beans from a schema, see JAXB.