Sure - SHOW US:
1. WHAT you do
2. HOW you do it
3. WHAT results you get
We can NOT see your screen so we have no idea what info you are entering into the connection dialog or whether it is the SAME info as what you used in sql*plus.
Probable corruption of the connections.xml file in your user settings for 188.8.131.52.089.
Try deleting and recreating that specific connection definition and click the Test button to make sure it works.
In your current state, SQL Developer cannot create the ConnectionInfo object for that connection name and is trying to call getConnectionType on a null object.
A discussion from February also indicates this is a known issue with 184.108.40.206SE, and possibly 220.127.116.11SE when using the OCI/Thick driver...