Some readers commented that, after they add JDBC driver for Microsoft SQL Server to their SQL Developer, the “New Connection” window (of SQL Developer) doesn’t open at all. I have downloaded the latest Java (1.6), SQL Developer and added jTDS driver then I have the same problem. I tried to debug the problem with my limited Java knowledge and I think there’s an incompatibility between jTDS and Java 1.6.
Oracle recommends to use Java 1.6 for SQL Developer so instead of trying Java 1.7, I tried to find the latest compatible version of jTDS and luckily I found it on my first try. So to fix the problem, all you need is to download and use 1.2.7 version of jTDS: jtds-1.2.7-dist.zip
Then you’ll be able to connect to Ms SQL Server or Sybase with your Oracle SQL Developer. For more information about using SQL Developer with Ms SQL Server and MySQL, please read my related blog post.