Bad form I did not do a practical search first, I found the cause of this is the jdk 1_4_2 is not enough, 1_5 is needed.
OK, I have a way round this one but it's not easy.
Basically there is one jar compiled with 1.5 instead of 1.4 that I have found so far. It does not use any 1.5 features itself, although it allows javadoc generation for 1.5 source code! It can therefore be readily recompiled for 1.4. Here are brief instructions.
PLEASE NOTE: ignore all references to Maven in the release notes etc for xjavadoc. The Maven build appears to be totally broken with all versions of Maven. Use cvs and ant.
Use CVS to get the source for xjavadoc:
cvs -d :pserver:email@example.com:/cvsroot/xdoclet checkout -P -D "2005-06-11 12:33" -- xjavadoc
Hit enter for the password.
Ensure you have Ant 1.6.5 on your system
Ensure you have junit.jar from junit3.8.1 on your classpath or in %ANT_HOME%/lib
Ensure your 1.4 java runtime is the first on the path etc.
execute ant to build the jar:
If all works you should get:
rename it to:
copy it over the one in %ECLIPSE_HOME%/plugins/org.jboss.ide.eclipse.xdoclet.core_1.5.0.RC1
BEWARE: I have only conducted the most cursory testing on this patch, but xdoclet now runs where as before it did not.
OK! It worked for me with a little workaround (over sgparry's one).
I followed the previous post step by step but Alas! no jar file found in target directory.
I just jar-ed it myself, zipping the whole xjavadoc directory inside target/classes and then renaming it as told.
I overwrote the eclipse jar and voilà... My xdoclet worked!
I've also had this problem. I installed jdk1.5.0_06, pointed to it in Window/preference menu: java/Installed JRE.
Then the build successeded.