Recently I wanted to play a bit with Eclipse and JPA. Thus I wanted to create a JPA project.
I got stuck when specifying the database connection, as editing the "Connection URL" (shown on the image) is not possible and I want to enter a (good, working) connection string to an Oracle RAC server which looks more or less like that:
In this case the wizard is trying to help the user by providing form entry of these values as opposed to typing in the string. I would agree that it would also be nice to be able to paste in the string you want to use. Generally speaking it wouldn't be a problem to use the form to achieve the URL you want to use, but if it really is a problem you can simply create a "Generic JDBC" connection profile. This will allow you to input any connection URL that you want, without any form to get in the way. It does require an extra bit of configuration, but it's pretty minimal.