I'm curious why the hard requirement that it should be spring based? You wish to implement all this from scratch?
If you're ok with an off-the-shelf solution which gives most of these features, then look into
Liferay community portal.
A quick check through your features:
LDAP Authentication : Yes
Pages - Tiles Way: Yes, custom pages can be authored using WYSIWYG UI, and they can have boxes of contents (called "portlets") showing different information (like the old iGoogle pages). But I'm not really sure what you mean by "Tiles" way.
RSS feeds : Yes
Forum : Yes, but they call it "message boards"
Mails : Yes, for messageboards, blogs and wikis
Wiki kind of Knowledge repository : Yes
Latest Update Dashboard : Not sure. For standard content like blogs and wikis, a "What's new" type of page is available.
Photo Gallery :
Yes
WorkFlows :
Yes
Basically, every little content box is called a "portlet". You get lots of out-of-the-box portlets (like blogs, wikis, messageboards) and you can also write your own custom portlets. It is itself based on Spring framework; your own portlets too can use spring if they want to. You can try out liferay community version with
tomcat bundle - it's free.
