Static Import in java with examples| Difference between static vs normal import

Static Import in java 5

static import is a java language feature introduced in version 5 alias code name as tiger version.

It was introduced to simplify the access of static variables and static members without using class names.

Before static import is introduced, we have normal import statements for every java class to use the methods and classes with using the class name. Here is a normal import for List class example

import java.util.List

How the java code looks like before the static import feature is introduced?

Normally in java coding, if we want to use any static member variables or a method of a class in our code,
we have to first import that class using the normal import keyword, after that, we have to use variables/methods with class name in the code (for example Math.E)).

Below is the example for normal import usage with accessing the member variables using a qualified class name.

import java.lang.\*;  
public class ImportDemo {  
 public static void main(String args\[\]) {  
  System.out.println("This is sample program without using static import functionality" + Math.E);  
 }  
}  

In the above program,

• we have used System and Math classes from the java.lang package.
• In the java program, we don’t need to import any java.lang package as the default package imported is the java.lang package for every program.
• imported java.lang package for this tutorial purpose

static import example

Now we will see the example for the static import feature.

We can use the static member variables of java.lang.System and java.lang.Math classes without a qualified class name.

import static java.lang.System.\*;  
import static java.lang.Math.\*;  
public class ImportDemo {  
 public static void main(String args\[\]) {  
  out.println("This is sample program without using static import functionality" + E);  
 }  
}  

out is static field in java.lang.System class and E is static member variable for java.lang.Math class

For using static member variable E in Math class in java.lang Package, we have coded by adding static import something like import static java.lang.Math.*; or java.lang.Math.E.

It is a good idea to define for each static member(Math.E) instead of all static members(Math.*) in the static import declaration.

Static import Advantages

It allows us to call the static members without using the class name in our code.

By making static import code statements make all the static members of that class are available to declare java class.

Static import can be used for static member variables as well as static members without referring to the class name in java code.

It simplifies the code readability for the constants.

Static import Disadvantages:-**

if we are importing the two same static constants from different classes in the same class. there is the possibility of ambiguity for the compiler to throw an error.

What is the difference between Static import and Normal Import

The basic difference between normal import and static import is normal import can call the member variables using the class name in the package.
static import can be defined and static member fields, can not refer to any class name, and used directly without a class name.

Conclusion

To Sum up, Learned Static import feature in java 1.5 version, this new syntax allows the developer to improve readability and clean code.

And also documented advantages and disadvantages, compare this with normal import example.