How to fix Eclipse validation error “No grammar constraints detected for the document”?

Question

Eclipse 3.5.2 is throwing an XML schema warning message:

No grammar constraints (DTD or XML schema) detected for the document.

The applica

Answer 1

Here's what worked for me. I was using schemas without version numbers (e.g. spring-beans.xsd, and not spring-beans-4.1.xsd) and they probably got updated upstream. I assume the problem was that Eclipse kept a dirty cache of the old versions.

Fix :
1. Go to Window -> Preference -> Network Connection -> Cache
2. Remove all cached schemas.
3. Delete all the no grammar constraints problems in problem view.
4. Re-validate the project.