JAXB 面试题与答案

Question: What are the disadvantages/non-goals of JAXB?

Answer: • Standardize generated Java
– classes generated by different
JAXB implementations may not be
compatible with each other
• Preserve XML equivalence
– unmarshalling XML to objects and
marshalling back to XML may not
result in equivalent XML
• Bind existing JavaBeans
to schemas
– can only marshal and unmarshal
classes generated by JAXB
– may be added later
• Schema evolution support
– can’ t modify previously generated
code to support schema changes
– must generated new code
• Allow generated Java to access
XML elements/attributes not
described in initial schema
• Partial binding
– unmarshalling only a subset
of an XML document
breaks round tripping
• Implement every feature of the
schema language
– it’ s tough to implement
all of XML Schema!
• Support DTDs
– focusing on XML Schema
– DTDs were supported in an earlier
version, but won’ t be anymore
– tools for converting DTDs to
XML Schemas exist