How to resolve the error "java.lang.IllegalStateException: No transactional EntityManager available"

If you get the below error while using Spring+JPA+Hibernate then try to wrap the method with
import org.springframework.transaction.annotation.Transactional;

@Transactional

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalStateException: No transactional EntityManager available
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:981)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:860)
javax.servlet.http.HttpServlet.service(HttpServlet.java:734)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845)
javax.servlet.http.HttpServlet.service(HttpServlet.java:847)

JBWEB000071: root cause
java.lang.IllegalStateException: No transactional EntityManager available
org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:267)
com.sun.proxy.$Proxy39.unwrap(Unknown Source) org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalStateException: No transactional EntityManager available
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:981)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:860)
javax.servlet.http.HttpServlet.service(HttpServlet.java:734)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845)
javax.servlet.http.HttpServlet.service(HttpServlet.java:847)

JBWEB000071: root cause
java.lang.IllegalStateException: No transactional EntityManager available
org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:267)
com.sun.proxy.$Proxy39.unwrap(Unknown Source)