Error – “Io exception: The Network Adapter could not establish the connection”.

Solution – When you stuck connecting db from Oracle sql developer. while you have correct user credential

Then something you are missing. in my case I had installed sql developer tool then install jdk 7 and while opening sql developer it asked for jdk path and I located jdk 7 java.exe path by which I am able to open the developer tool but on connecting the db it throws
“Io exception: The Network Adapter could not establish the connection”

So I finally installed JDK 6 and from another oracle sql developer tool locate the path of java.exe from jdk6 folder.. now i am able to connect to the db successfully.

Step1 – Delete the previous oracle sql developer tool
step2 – Downlod oracle sql developer tool http://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/index.html
Step3- Extract the zip and open sqldeveloper.exe
Step4- Locate the java.exe from JDK 6 folder

That’s it