SQL Error: ORA-01940: cannot drop a user that is currently connected

SQL Error: ORA-01940: cannot drop a user that is currently connected
01940. 00000 -  "cannot drop a user that is currently connected"
*Cause:    Attempt was made to drop a user that is currently logged in.
*Action:   Make sure user is logged off, then repeat command.

Issue: When I am trying to drop a user from Oracle database, I am getting the above error though my application is in stopped stated which uses this schema. 
 Basically I am not a DBA to find out SID and SERIAL number and issue command to kill the session.

Solution: Use "Oracle SQL Developer" if you already having it. It is very simple and quick process. I will demonstrate how to achieve this. Just follow below steps.

 We can kill user session with SQL Developer option.

Step 1: Login to SQL Developer with system user account or any other user who are having DBA privileges and try dropping a user.

 

Step 2: Go to Tools -> Monitor Sessions.

Step 3: Select your database connection from the drop down list.

Step 4:It displays all user session which are active.

 Step 5: Select the user session you want to kill and click "Apply" button to kill the session.

 

 Step 6: You will get the below confirmation message.

 

 This demonstration is intended only for testing or demo environments who are learning the technology and not for advanced users and DBA.