Application developers often need to make use of a persistence layer in their projects; one of the preferred methodologies to perform this in Karaf is to make use of the Java Persistence API and OpenJPA.
In the Installing OpenJPA modules in Apache Karaf recipe, we learned how to install OpenJPA in Karaf; in this recipe, we'll make use of the JPA and OpenJPA to build a simple application that persists recipes to a database using a
RecipeBookService class, which will hide the complexities of data storage and retrieval from its users.
The ingredients of this recipe include the Apache Karaf distribution kit, access to JDK, and Internet connectivity. Sample code for this recipe is available at https://github.com/jgoodyear/ApacheKarafCookbook/tree/master/chapter7/chapter7-recipe3. Generally, you'll also need to perform the steps outlined in the Installing OpenJPA modules in Apache Karaf recipe.