2. Obtaining EntityManagers
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## 2. Obtaining EntityManagers

    public EntityManager createEntityManager();
    public EntityManager createEntityManager(Map map);

The two `createEntityManager` methods above create a new `EntityManager` each time they are invoked. The optional `Map` is used to supply vendor-specific settings. If you have configured your implementation for JTA transactions and a JTA transaction is active, the returned `EntityManager` will be synchronized with that transaction.

### Note

OpenJPA recognizes the following string keys in the map supplied to `createEntityManager`:

- `openjpa.ConnectionUserName`

- `openjpa.ConnectionPassword`

- `openjpa.ConnectionRetainMode`

- `openjpa.TransactionMode`

- `openjpa.<property>`, where <property> is any JavaBean property of the `org.apache.openjpa.persistence.OpenJPAEntityManager`.

The last option uses reflection to configure any property of OpenJPA's `EntityManager` implementation with the value supplied in your map. The first options correspond exactly to the same-named OpenJPA configuration keys described in Chapter 2, Configuration of the Reference Guide.

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