The MS TechEd conference is being held up as an ideal of what a developer community should be. It is akin to a court established by the central authority for all things .NET -- Microsoft. They invite people who they think will enhance their court, weigh in with good ideas, and generally convince the ruler that he is right. Microsoft invites attendees. They won't invite jerks. This isn't a complete portrayal of the MS online community, but as Ted Neward chose to compare an invited conference to weblogs and TSS, it's fair, I think.
The online Java community (bloggers, active mailing lists, irc) is a much more anarchic beast with democratic (and meritocratic variations thereupon) leanings amongst the more established elements. There is, purposefully, no center of the Java world. Sun has attempted to position themselves as first-among-equals, and may be, but that is a very arguable claim at that. The online Java communities are much better compared to salons. Talented people aggregate around someone who provides a convenient place for them to aggregate: JUGs, the ASF, Codehaus, TSS, JavaBlogs, OpenSymphony, etc. There is considerable overlap, but there are specific focal points. People or organizations sponsor these focal points. Sometimes sponsorship is simply being interesting, other times it is financial, sometimes is is merely providing infrastructure
To look deeper, there are actually a lot of completely different Java communites, as there are MS communities. Java has been quite embraced by the open source movement, or vice versa (the brine doesn't get cucumbered, the cucumber gets pickled =) As such a lot of the OSS community template has been absorbed by Java communities. On the other hand, there are also definite communities around the major vendors. There is, for instance, a quite strong (if measured in abilities of the people involved and interest in the technology) BEA users group near me. Many people who consider themselves members of this group don't really grok open source -- but others are deeply involved with some very high profile projects. This is a community as well.
The Java weblog community has a lot of prima donnas with big egos, who stand up on self-built soap boxes and spout rubbish. Others spout gems of wisdom. Go read weblogs.asp.net and let me know if you see anything different (if you are bored, mention object relational mapping there ;-).
If you go to somewhere like FOO camp you will probably see a big, cuddly, hugfest like TechEd -- except in this case not particularly Java focused (the creme of the Java community typically doesn't care much about Java in and of itself, so overlaps highly with people simply doing interesting things) and invited by a publisher instead of an 8000 lb. gorilla.