divide your classes into different folders
- Util folder - contains classes related to utility
- Each folder is called a package
- You can have a folder in a folder (package in a package)
src > main > java
- package starts from here
src > main > resource
- many config/template files listed here

How do we create packages?

package com.leejun.demo.app*; // importing everything
package com.leejun.demo.app.C; // importing C
 
public class A {
	public static void main(String[] args){
		C obj = new C();
	}
}

Visual Studio
- If you click under package > Move to package, then the editor will automatically make the necessary structures and put your file there
- inside the system explorer, we have the com folder > leejun folder > … >
You don’t need to import the package of the same class

자바의 대표적인 내장 패키지

java.lang
- imported automatically
- contains basic classes like > String, Math, Object
java.util
- Collections, Date class
java.io
- input, output
java.nio
- I/O