How To Access Package From Another Package

How to access package from another package

There are three ways to access the package from outside the package.

1.    import package.*;

2.    import package.classname;

3.    fully qualified name.

Fig Access Package Form Another Package 

1) Using packagename.*

If you use package.* then all the classes and interfaces of this package will be accessible but not subpackages.

The import keyword is used to make the classes and interface of another package accessible to the current package.

Example of package that import the packagename.*

     //save by A.java  

     package pack;  

     public class A{  

     public void msg(){System.out.println("Hello");}  

     }    

//save by B.java  

package mypack;  

import pack.*; 

class B{  

  public static void main(String args[]){  

   A obj = new A();  

   obj.msg();  

  }  

}  

Output:Hello

2) Using packagename.classname

If you import package.classname then only declared class of this package will be accessible.

Example of package by import package.classname

     //save by A.java  

     package pack;  

     public class A{  

     public void msg(){System.out.println("Hello");}  

    }  

    //save by B.java    

    package mypack;  

    import pack.A;  

     class B{  

     public static void main(String args[]){  

      A obj = new A();  

     obj.msg();  

     }  

}  Output:Hello

3) Using fully qualified name

If you use fully qualified name then only declared class of this package will be accessible. Now there is no need to import. But you need to use fully qualified name every time when you are accessing the class or interface.

It is generally used when two packages have same class name e.g. java.util and java.sql packages contain Date class.

Example of package by import fully qualified name

    //save by A.java   

    package pack;  

    public class A{  

    public void msg(){System.out.println("Hello");}  

     }  

    //save by B.java   

     package mypack;  

     class B{  

     public static void main(String args[]){  

      pack.A obj = new pack.A();//using fully qualified name  

       obj.msg();  

      }  

Output:Hello