Define package in Java.

 In Java, a package is a namespace that organizes a set of related classes and interfaces. Packages provide a way to group related classes and interfaces, and to ensure that the names of these classes and interfaces are unique within the Java ecosystem.

To create a package in Java, you need to use the package keyword followed by the name of the package at the top of your source file. For example:

package com.example.mypackage; public class MyClass { // class definition goes here }

In this example, the MyClass class is part of the com.example.mypackage package.

To use a class or interface from a package in your code, you need to import it using the import keyword. For example:

import com.example.mypackage.MyClass; public class Main { public static void main(String[] args) { MyClass c = new MyClass(); // use c here } }

In this example, the Main class imports the MyClass class from the com.example.mypackage package and creates an instance of it.

Packages are typically used to group related classes and interfaces and to prevent naming conflicts between classes with the same name. They can also be used to control access to classes and interfaces by making them package-private (accessible only within the package) or public (accessible from any class).

To make a class or interface package-private, you can omit the public keyword from its declaration. For example:

package com.example.mypackage; class MyClass { // class definition goes here }

In this example, the MyClass class is package-private, which means that it is only accessible from within the com.example.mypackage package.

To make a class or interface public, you can use the public keyword in its declaration. For example:

package com.example.mypackage; public class MyClass { // class definition goes here }

In this example, the MyClass class is public, which means that it is accessible from any class.