81 words
unwrap(cls) - JPA EntityManager's method
Methodjavax.persistence.EntityManager
T unwrap(
Class<T> cls
)
Return an object of the specified type to allow access to the
provider-specific API. If the provider's
EntityManager
implementation does not support the specified class, the
PersistenceException is thrown.- Parameters:
cls- the class of the object to be returned. This is normally either the underlyingEntityManagerimplementation class or an interface that it implements.
- Returns:
- an instance of the specified class
- Throws:
PersistenceException- if the provider does not support the call
- Since:
- JPA 2.0
This documentation page is derived (with some adjustments) from the open source JPA 2 RI (EclipseLink)
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
Object Relational Mapping (ORM) JPA 2 providers include Hibernate, EclipseLink, TopLink, OpenJPA and DataNucleus.
Object DB is not an ORM JPA implementation but an Object Database for Java with built in JPA 2 support.
Which JPA is Faster?
See a comparison of Hibernate, EclipseLink, OpenJPA, DataNucleus, MySQL, PostgreSQL, Derby, HSQLDB, DB4O by Versant, H2 Database, SQLite and ObjectDB
in the JPA Benchmark.
