Java Packages Tutorial with Examples

Package in Java :

Java uses the concept of package to grouped classes together.

Packages are used to reuse an existing without physically copying the code.

There are two types of packages -

Built-in package
User-defined package

1. Built-in package / Predefined Package

Ther are predefined and the part of the language.

Java has many built-in packages like - util, lang, awl, sql,...etc.

2. User-define package

They created by programmer package keyword is used to declare a package.

The “import” keyword is used to import package in a class.

Example -

// calc.java

// web design house

//online promotion house

package P;
public class Calc{
   public static int add(int a,int b){
       return a+b;
   }
   public static int sub(int a, int b){
       return a-b;
   }
}

//Save file with - Calc.java
// javaC_-d_.Calc.java
import P.Calc;
public class Main {

public static void main(String[] args) {
// write your code here
int r = Calc.add(10,30);
System.out.println("sum = "+r);
r = Calc.sub(10,5);
System.out.println("sub = "+r);

}

}