Static Import

Static import

Introduced in  Java 5

Import statement was enhanced to provide greater keystroke-reduction capabilities.

 Static import is use when you want to access Class static members.

Example:

File: First.java

import static staticImport.Second.*;

public class First

{

       public static void main(String[] args)

       {

              System.out.println(firstVar);

              printfirstVar();

       }

}

File : Second.java

public class Second

{

              final static int  firstVar= 34;

             

              static void printfirstVar()

              {

                     System.out.println(firstVar);

              }

}

Output:

34

34

Problem:

Ambiguity of static members:

If we import from two classes which use same static variables then compiler will in ambiguity to decide which variable class variable to use.

Example:

File:First.java

import static staticImport.Second.*;

import static staticImport.Third.*;

public class First

{

       public static void main(String[] args)

       {

              System.out.println(firstVar);         // Error since compile not able to decide which firstVar we want to use, either of Second.java or Third.java

             

printfirstVar();                   // Error: reason is same as above

       }

}

File: second.java

public class Second

{

       final static int  firstVar= 34;

             

       static void printfirstVar()

       {

              System.out.println(firstVar);

       }

}

File: Third.java

public class Third

{

       final static int  firstVar= 34;

      

       static void printfirstVar()

       {

              System.out.println(firstVar);

       }

}