A package is a single folder (directory) containing a group of related classes and interfaces.
A package declaration, if used, must be the first thing in the file, and describes the folder in which it occurs. For example, the declaration
specifies that the class is to be found in the directory
The import declaration can be used to make an entire package, or individual classes within a package, more easily accessible to your Java program.
package declaration is specified in a file, the "default
package" is used. The default package cannot be imported by other packages.