where to define packages in java code example

Example 1: What is packages in java

Package is a mechanism to group related classes ,interfaces and enums 
in to a single module.
Package can be declared using the following statement :
Syntax : package <package-name>
Coding Convention : package name should be declared in small letters.
package statement defines the namespace.
The main use of package is
1) To resolve naming conflicts
2) For visibility control : We can define classes and interfaces that are 
not accessible outside the class

Example 2: java packages example

// import <package>			-> Imports the whole package
// import <package>.<class> -> Imports a certain class
import java.util.Scanner;