JDeveloper: JboConfigUtil Exception

So you were tinkering with JDeveloper (any version), and while trying to use an online database for your new entity / whatever, you instead got this:

SEVERE: null at oracle.jbo.dt.objects.config.JboConfigUtil.getConfigurationNameList(JboConfigUtil.java:235)
java.lang.NullPointerException
 at oracle.jbo.dt.objects.config.JboConfigUtil.getConfigurationNameList(JboConfigUtil.java:235)
 at oracle.jbo.dt.objects.config.JboConfigUtil.getConfigurationNameList(JboConfigUtil.java:225)
 at oracle.jbo.dt.jdevx.ui.pkg.XPKConnectPanel.updateConfigurations(XPKConnectPanel.java:703)
 at oracle.jbo.dt.jdevx.ui.pkg.XPKConnectPanel.onFinish(XPKConnectPanel.java:684)
 at oracle.jbo.dt.ui.main.dlg.DtuWizardPanelDialog.okAction(DtuWizardPanelDialog.java:362)
 at oracle.jbo.dt.ui.main.dlg.DtjDialog.dismissDialog(DtjDialog.java:221)
 (...)

You've already created the data source, set it in Project Properties [on the model project] / ADF Business Components, reported the feedback, saw it will be fixed in JDeveloper 13... but until then:

Go to the .jpx file of your model project (the file with the two cogwheels icon), General / Connection, select the connection.