I already posted a video that showed how to get a project from NetBeans into JDeveloper.
Dana has a blog that shows a simpler approach for NetBeans to JDeveloper migration. If you are using Maven in your NetBeans project, then you can use the Maven extension for JDeveloper to bring in the project.
One thing that I forgot to show, and Dana's video does show is that the migration is not a one-way street; in fact you can now use any of the IDEs to work on your code - as they are both sharing the same source files. Then you can pick and choose the tool you are comfortable with.