I have a jar file named
Using "Default Package" package for libraries or even for a project is highly discouraged.
If you use default package then the classes name should be unique or else they will override all the
Now coming to your situation. To use your
stdlib.jar if you've added it in your library then you should be able to use it.
You can use your
stdlib.jar from your default package of the project in which you are using it. Other than default package you cannot use it as it will search your
stdlib.jar class in that package.
Hope this makes you clear. Thanks.