Sai,
You can download EclipseLink 2.5 libraries.
The JAR files that should be used for JPA persistence service are:
eclipselink.jar
javax.persistence_2.1.0.v201304241213.jar
org.eclipse.persistence.jpa.modelgen_2.5.1.v20130918-f2b9fc5.jar
org.eclipse.persistence.jpars_2.5.1.v20130918-f2b9fc5.jar
Create a User library containing the above JARs. Then, for a JPA 2.0 project on the Java > Build Path properties page, remove the Eclipse Link 2.1.1 containers and replace them with the User Libraries you created. For a new project, you can select the User library during the ‘Install JPA Facet’ wizard.
You can modify the JPA facet to 2.1 for the project from here :<workspace dir>/<project>/.settings/org.eclipse.wst.common.project.facet.core. Once done refresh the project and modify the persistence.xml to support JPA 2.1.
Hope this helps.
Let us know how it works for you.