迁移到Java 8后，Jaxb无法解析XML

Question

I Am making to move to java 8, and in the process jaxb fails to parse an xml configuration.

While changing nothing but the JDK, the same code and file is successfully parsed using java 7, but does not parse correctly on java 8.

Note that there is no exception thrown but the data does not appear in the object that the xml is unmarshald into.

Any ideas what might cause this very annoying failure.

Answer 1

I have found the cause of the problem.

I have not researched the code, but it seems that the code behind JAXB or SAX parser has changed from java7 to 8, and is less forgiving in java 8. (This might also be due to changes in compiler/jvm itself )

The parsing was done with annotations. and it was something that looks like the following:

 @XmlRootElement(name = "component_configuration") @XmlAccessorType(XmlAccessType.NONE) public class ComponentConfiguration extends Configuration {} @XmlRootElement(name="configuration") @XmlAccessorType(XmlAccessType.NONE) public class Configuration {} 

In the java 7 version this kind of "game" was either permitted of was successfully parsed (by luck if you ask me) but in java 8 it didn't work any more.

I ended writing the model again correctly and everything worked fine.

Hope this will help someone else thats braking balls over jaxb compatibility.

Answer 2

I've found another difference between handling Jaxb on Java 7 versus Java 8. I've reduced the issue to a simplified example. (changed the categories so it's non-work-related etc) When the setter for a List is called by the Unmarshaller:

• when run in Java 7 the setter will be called with data in the List
• when run in Java 8 the setter will be called only with an empty List object which apparently gets populated later in the unmarshalling process.

The difference I experience is that I must not have the setter do any processing on the List, but rather have a process that is invoked only after the overall object is unmarshalled. Or to sum it up, "don't do any processing in the setter". I've posted the revised example in the question at Difference in JAXB Java 7 versus Java 8