Vincent's feedback reminded me about something else we probably should look at. Vincent proposed to add a dependency on the Xerces/Xalan XML serializer. As noted, I'd prefer to stick to plain JAXP. But yes, with Java 1.4 JAXP is built in so the 4 XML JARs are actually not necessary anymore (would one think). There are several things we can do:
1. Just remove them. Good: - Makes the distribution a lot smaller. Problems: - Early Java 1.4 and 1.5 JVMs contain (very) old and buggy JAXP implementations. It's a good idea to always replace them (this gets me to solution 2). - Our test code has a (useful) dependency on Xalan's XPath API. Java 1.4 provides an old JAXP version without XPath support (javax.xml.xpath, available with Java 1.5). So we've got a problem here for the time being. 2. Move the 4 JARs to a lib/endorsed directory and adjust our scripts to insert them into the bootclasspath which has the effect of overriding the JAXP implementation of the JVM. Good: - This also makes it much clearer that these JARs are not a dependency like every other. Problems: - User might wonder why the JARs are suddenly in a different place. Open Question: - Should we start programming against JAXP 1.3 (because of the XPath API)? But that requires that all users install JAXP 1.3 implementations in their environments which can be problematic for older application servers (like an old WebSphere which is used in many bigger companies). I'd say we should stick to JAXP 1.2 until we can move to Java 1.5. 3. Remove the implementations but not the xml-apis.jar with the JAXP 1.3 API. Good: - Allows us to use the XPath and Validation facilities. Problems: - Pre-programmed user problems because old JAXP implementations are present and people don't know how to replace them or are not allowed to replace them or it's a stability danger to the whole application server when replacing it once you figure out how to do it. I guess it's clear that only solution 2 makes sense if we want to change something. And that would be revisited once we move to Java 1.5. Have I missed something? Jeremias Maerki
