can't see java file but debugger shows it is present and can access using reflection

I am debugging an android application to find out the implementation of something. I am using a debugger in Android studio from which I came to know that there is a java file that is responsible but that java file is hidden and debugger showing that the file is present at runtime. Although, I can access the functions using Reflection, but can't see the source code.

How can I see the source code of a java file which is hidden?