Supplier in Java 8 with Examples | get() method

What is supplier in Java 8?

As a name suggest, Supplier is a Functional Interface which does not take any arguments but produces a value.

It is part of java.util.function package and introduces in Java 8.

Suppliers are useful when we don’t need to supply any value and obtain a result at the same time.

Supplier is contains only one abstract method :

• get()

Return type is T - the type of results supplied by this supplier.

Lest see simple example of supplier interface.

Example 1 : Print random number using Supplier Interface

import java.util.function.Supplier;

public class SupplierDemo {

    public static void main(String[] args) {

        Supplier<Double> supplier1 = () -> Math.random();
		
	Supplier<Integer> supplier2 = () -> (int)(Math.random()*10);
		
	System.out.println("Random value from 0 to 1 : "+ supplier1.get());
	System.out.println("Random value from 0 to 1 : "+ supplier1.get());
		
	System.out.println("Random value from 0 to 9 : "+ supplier2.get());
	System.out.println("Random value from 0 to 9 : "+ supplier2.get());
         
    }
    
}
Output :
Random value from 0 to 1 : 0.5275071504631775
Random value from 0 to 1 : 0.2566787022560659
Random value from 0 to 9 : 4
Random value from 0 to 9 : 8

In first supplier, we are getting random value between 0 to 1 only. And in second supplier, we are getting integer random value between 0 to 9.

As you can see, we does not pass any arguments it is only return result.

 

Example 2 : Print List of String and Integer using Supplier

import java.util.Arrays;
import java.util.List;
import java.util.function.Supplier;

public class SupplierDemo {

    public static void main(String[] args) {

        Supplier<List<String>> supplier1 = () -> List.of(
                "Java", "JavaScript", "Python", "Php", "Angular", "C#", "C++");    
        
        Supplier<List<Integer>> supplier2 = () -> Arrays.asList(
                1, 2, 3, 4, 5, 6, 7, 8);
                
        
        System.out.println(supplier1.get());
        
        System.out.println(supplier2.get());
        
    }
    
}
Output :
[Java, JavaScript, Python, Php, Angular, C#, C++]
[1, 2, 3, 4, 5, 6, 7, 8]

Happy Coding.

Other Java 8 articles :-

• Lambda Expression in Java
• Predicate in Java 8