- It is very much possible that you may have multiple JDeveloper versions installed on your workstation. For example, 11g, 12c and possibly more than one version for each. You would want to make sure that you are opening your applications in proper version of JDeveloper.
- You may have different stream of code development in progress at the same time for your application and it will be nice to organize that in different folders.
- Also, if you are coming from Eclipse background, you may be missing workspace concept which is default for eclipse.
Create a short cut using something like this, which will create workspace for 12.1.3.
Or modify it for 12.1.2 as shown below.
Be sure to import preferences from previous workspace, so that you do not have to re-configure jdeveloper preference. You will be prompted for this only first time when you start JDeveloper with specific shortcut.
Now you can check out code in D:\jdev121300\ws1 and work with 12.1.3 and that will be independent of code checked out for 12.1.2 in D:\jdev121200\ws1. Note that folder names are mapped to jdeveloper version for easier identification.