I've run this morning into issue which is already discussed in this forum.
I haven't found relevant thread to post into, so I'm creating a new one.
I've tried to debug this problem and I found this:
First, I made a Project > Maven > Update Project Confguration
And after this, all NameSpace resolving was OK.
When using Project > Spring Tools > Add Spring Project Nature : DIFF
This is what is added
And With these changes the NameSpace resolving breaks.
diff -r first/.project second/.project
Then I tried to remove the nature, but until I run again "Update Project Configuration" (Maven), it won't repair
Not even restarting STS works.
This ISSUE can be related to this:
But obviously this is related to Spring "Beans Validator" plugin (or whatever it is), as we can get rid of these Validation marks through disabling Spring > Project Validators > Beans Validator > XSD Tool Annotation Rule
So that means, the namespaces are resolved correctly outside of Spring Validator
STS Version: 2.9.1.RELEASE (201203221000)