Jar file and db4o file

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1

I am creating a java application using the db4o db.
So I want the db4o db file to be inside the jar file of the application.
So how can I find a file inside the jar file?

ObjectContainer db=Db4o.openFile(Util.DB4OFILENAME);
2

It’s a read only file? Each time your program runs the jar files are extracted and executed. When the stops you will lose the data. Is it ok?