I work on a web application that uses Hibernate(3.2.6), Hibernate Validate(3.0.0), Hibernate Search(3.0.1), Hibernate EntityManager(3.3.1) and Hibernate Annotations(3.3.1).

Trying to upgrade them to Hibernate(3.5.4), Hibernate Validate(4.1.0), Hibernate Search(3.3.0), Hibernate EntityManager(3.6.0) and Hibernate Annotations(3.5.6). I have the dependencies independently declares in pom.xml. I keep getting Maven build error:Error building POM (may not be this project's POM).Project ID: org.hibernate:hibernate-validator:jar:null Reason: Cannot find parent: org.hibernate:hibernate-validator-parent for project: org.hibernate:hibernate-validator:jar:null for project org.hibernate:hibernate-validator:jar:null
I manually installed all these libraries and tried multiple times to check if I got the correct versions. Everytime the error message picks some library and spits out this message.

Can anyone help me understand what the issue is?

I don't know what Maven is trying to say, maybe if you post your pom.xml and the complete error message we can figure it out.

Anyway with the exception of Search, Validator and Shards, all other hibernate libraries are now released as one project so you should always choose matching versions (EntityManager 3.6.0.Final, Core 3.6.0.Final, Annotations 3.6.0.Final), maybe that solves the maven error.

As Sanne is saying, you would need to post you pom and post the full maven stack trace (try running with -X).
Also, if you are using Hibernate Validator 3.x and you are planning to upgrade to 4.x you actually have to change a few things. Hibernate Validator 4.x is based on a new code base implementing the JSR 303 (Bean Validation). In fact Hibernate Validator is the reference implementation of this spec.

--Hardy