Java 8 Supplier Interface example

In this blog post, I will be explaining how the Java 8 functional interface Supplier works. To know more about functional interfaces, you can refer this blog post.

Edit

The Supplier interface provides a method called get.  This method does not accept any arguments. It can return any data type.

Supplier example with Integer return type.

Consider the following code snippet:

public static void main(String[] args) {Supplier<Integer> getRandom = () -> new Random().nextInt(100);System.out.println("Random number 1 = "+getRandom.get());System.out.println("Random number 2 = "+getRandom.get());}

Here, we have implemented the Supplier.get method using a lambda expression.  This get method simple returns a random integer less than 100. So when this code is executed, it will print the following output:

Random number 1 = 98Random number 2 = 89

Supplier example with Date as return type

Consider the following code snippet:

public class SupplierDemo {public static void main(String[] args) {Supplier<Date> dateGenerator = () -> new Date();System.out.println("Date is "+dateGenerator.get());}

Again, we have implemented the Supplier.get method using a lambda expression.  This get method simple returns a date object. So when this code is executed, it will print the following output:

Date is Sun Nov 11 13:27:43 IST 2018

You can get the source code for this example along with the code for other Java 8 examples at the Github repository here.










































Comments











Post a Comment























Popular posts from this blog









How to use logging in SpringBoot with code samples




















Image







In this article, we will learn how to use logging in SpringBoot. Introduction There are several Java logging frameworks like logback, log4j, and so on. Spring Boot supports out-of-the-box support for logback. Let us learn how to use logging in SpringBoot with logback. Step 1 – Create a New Maven Project Create a new Maven project. (Refer to  this  blog post). This will create a project in Eclipse as follows:   Step 2 – Add the Spring Boot Dependencies Add the spring-boot-starter-web  dependency to the pom.xml . So, the pom.xml  should look as follows: <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">  <modelVersion>4.0.0</modelVersion>  <groupId>com.learnjava</groupId>  <artifactId>learnjava-springboot-logging-example</artifactId>  <version>0.0.1-SNAPSHOT&








Read more










Python While Loop with code samples





















Much like a Java while loop, you can use a Python while loop to repeatedly execute a block of code as long as a condition is true. In this article, we will learn more about the Python while loop. Python While loop Syntax A while loop in Python has the following syntax: while <condition>:  loop body The while keyword is followed by a condition. If the condition evaluates to true, the body of the loop is executed. Once the body of the loop is completed, the condition is checked again and this is repeated until the condition evaluates to false at which point the loop is exited. While loop Sample Code The following code demonstrates how you can use the while loop: num=10counter=1total=0while counter<=num: total += counter counter+=1print("sum of first 10 numbers is",total) This code adds the numbers from 1 to 10 and prints the sum. It uses a while loop to iterate from 1 to 10. The while loop checks the condition counter <= num and if so adds the current value of count








Read more










How to convert a List to a Set





















In this blog post ,I will be showing you how you can convert a List to a Set. Consider the following code snippet: public class ListToSetDemo {public static void main(String[] args) {List<Integer> list = Arrays.asList(5,3,11,15,9);//Method 1Set<Integer> set = new HashSet<Integer>(list);System.out.println("Set is "+set);//method 2Set<Integer> set2 = new HashSet<Integer>();set2.addAll(list);System.out.println("Set is "+set2);}} This code demonstrates two ways to convert a List to a Set. Method 1 Here, we are creating a new HashSet . We are invoking the constructor  that accepts a Collection object. Here, we are passing in the input list to this constructor.   Method 2 Here again, we are creating a new HashSet . However, we are using the default constructor. We are then invoking the addAll  method and passing in the input list.   When you run this code, it will print the following output: Set is [3, 5, 9, 11, 15]Set is [3, 5, 9, 11, 15] No








Read more