Java marshaller performance

Make sure you create the JaxB context instance only once, creating the context takes some time as it uses reflection to parse the object's annotations.

Note that the JAXBContext is thread safe, but the marshallers\unmarshallers aren't, so you still have to create the marshaller for every thread. However I found that creating the marshallers when you already hold a jaxb context is pretty fast.

Seconding the Use of JibX. Like questzen, I found that JibX was 9 times faster than JAXB in my performance tests.

Also, make sure you have woodstox on the classpath when using JibX. I found woodstox's Stax Implementation is roughly 1050% faster than the Java6 implementation of Stax.

Byeond other good suggestions, I suggest there is something wrong with the way you use JAXB -- it is generally reasonably well performing as long as:

• You use JAXB version 2 (NEVER ever use obsolete JAXB 1 -- that was horribly slow, useless piece of crap); preferably a recent 2.1.x version from http://jaxb.dev.java.net
• Ensure that you use SAX or Stax source/destination; NEVER use DOM unless you absolute must for interoperability: using DOM will make it 3 - 5x slower, without any benefit (it just doubles object model: POJO -> DOM -> XML; DOM part is completely unnecessary)
• Ideally use fastest SAX/Stax parser available; Woodstox is faster than Sun's bundled Stax processor (and BEA's ref. impl. is buggy, no faster than Sun's)

If JAXB is still more than 50% slower than manually written variant, I would profile it to see what else is going wrong. It should not work slowly when used properly -- I have measured it, continuously, and found it so fast that hand-writing converters is usually not worth time and effort.

Jibx is a good package too btw, so I have nothing against trying it out. It might still be bit faster than JAXB; just not 5x or 10x, when both are used correctly.