Register sensible default HTTP Message Converters based on what is available in the classpath [SPR-6375]

[spring-projects-issues]

Keith Donald opened SPR-6375 and commented

The new mvc namespace gives us a nice opportunity to add additional sensible defaults.
Proposal:

• Register support for JAXB if Java 6+
• Register support for JiBX if in classpath
• Register support for JSON if Jackson in classpath

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Affects: 3.0 RC2

Referenced from: commits 81d7f5b

[spring-projects-issues]

Arjen Poutsma commented

I'm not sure about Jibx, but we can detect Jaxb2 for sure.

JAXB2 can also be used on JDK 1.5, so I guess we just have to test for a JAXB2 class, rather than enable it on JDK 1.6 only.

[spring-projects-issues]

Dave Syer commented

I'm not convinced yet, either. What if my application is working fine with an auto-detected JAXB converter, and then I add Jackson to the classpath? Suddenly it breaks with no warning?

[spring-projects-issues]

Arjen Poutsma commented

Jackson and JAXB2 are not mutually exclusive (one is JSON, the other XML), so I don't understand what you mean.

[spring-projects-issues]

Dave Syer commented

I mean that I might be using JAXB in one REST endpoint and then I add another jar file with a JSON endpoint and a transitive dependency on Jackson, and suddenly my old application code breaks at runtime. Make sense?

[spring-projects-issues]

Arjen Poutsma commented

No, because we will detect for Jackson and JAXB2 separately, and can include them both if found, i.e. the two are not mutually exclusive.

[spring-projects-issues]

Arjen Poutsma commented

Done. JAXB2 and Jackson are now detected and their respective message converters are registered automatically.