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The bundle pax-jdbc-config follows a different approach. It creates and publishes a DataSource and a XADataSource from a config with the help of an existing DataSourceFactory service. Simply install the necessary bundles and create a config with the factory pid org.ops4j.datasource. In Apache Karaf this means to create a config with a name like etc/org.ops4j.datasource_-*.cfg.
The created DataSource will also be given the osgi.jndi.service.name property. So if aries jndi is present it will automatically be available using jndi. So it can be used in a persistence.xml.
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