26. Legacy Bootstrapping

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The legacy way to bootstrap a SessionFactory is via the `org.hibernate.cfg.Configuration` object.
`Configuration` represents, essentially, a single point for specifying all aspects of building the `SessionFactory`: everything from settings, to mappings, to strategies, etc.
I like to think of `Configuration` as a big pot to which we add a bunch of stuff (mappings, settings, etc) and from which we eventually get a `SessionFactory.`

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There are some significant draw backs to this approach which led to its deprecation and the development of the new approach, which is discussed in  [Native Bootstrapping](#bootstrap-native).
`Configuration` is semi-deprecated but still available for use, in a limited form that eliminates these drawbacks.
"Under the covers", `Configuration` uses the new bootstrapping code, so the things available there as also available here in terms of auto-discovery.

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You can obtain the `Configuration` by instantiating it directly.
You then specify mapping metadata (XML mapping documents, annotated classes) that describe your applications object model and its mapping to a SQL database.

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<pre class="prettyprint highlight">`Configuration cfg = new Configuration()
    // addResource does a classpath resource lookup
    .addResource("Item.hbm.xml")
    .addResource("Bid.hbm.xml")

    // calls addResource using "/org/hibernate/auction/User.hbm.xml"
    .addClass(`org.hibernate.auction.User.class`)

    // parses Address class for mapping annotations
    .addAnnotatedClass( Address.class )

    // reads package-level (package-info.class) annotations in the named package
    .addPackage( "org.hibernate.auction" )

    .setProperty("hibernate.dialect", "org.hibernate.dialect.H2Dialect")
    .setProperty("hibernate.connection.datasource", "java:comp/env/jdbc/test")
    .setProperty("hibernate.order_updates", "true");`</pre>
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There are other ways to specify Configuration information, including:

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• Place a file named hibernate.properties in a root directory of the classpath
• Pass an instance of java.util.Properties to Configuration#setProperties
• Via a hibernate.cfg.xml file
• System properties using java -Dproperty=value </div> </div> </div>