JPA(Java Persistence API) Tutorial-Creating one EntityManagerFactory by application

Creating one EntityManagerFactory by application

When controlling database transactions programmatically one EntityManagerFactory per application is usually
used. This is the optimal approach since loading an EntityManagerFactory has a high performance cost; JPA will
analyze the database, validate entities and perform several other tasks when creating a new EntityManagerFactory.
Thus it is unviable to create a new EntityManagerFactory per transaction.
Below is a code that can be used:

import javax.persistence.*;
public abstract class ConnectionFactory {
private ConnectionFactory() {
}
private static EntityManagerFactory entityManagerFactory;
public static EntityManager getEntityManager(){
if (entityManagerFactory == null){
entityManagerFactory = Persistence.createEntityManagerFactory("MyPersistenceUnit");
}
return entityManagerFactory.createEntityManager();
}
}

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