Provides JpaTemplate's data access methods that mirror various
EntityManager methods. See the JPA EntityManager javadocs for details
on those methods.
Note that lazy loading will just work with an open JPA EntityManager,
either within a Spring-driven transaction (with JpaTransactionManager or
JtaTransactionManager) or within OpenEntityManagerInViewFilter/Interceptor.
Furthermore, some operations just make sense within transactions,
for example: flush.