All this does is declare that the source file is part of the package " traer.physics"...
This declaration is necessary in any Java program.

That sounds incredibly redundant, so: A package is an organization of Java source files... for example, processing.core is a package, as is processing.opengl.

The import statement merely imports another part of the library... it is probably necessary. Since the required classes are stored in a different package, the import statement is required.

So, if Im creating my own library in processing, simply I can omit this line:

 

and I use import like this:

 

import physics.*;

 

With physics being the name of the folder. It´s all correct?