Typically, we would write the following few lines to bring up a hello world API with Spark:

1 import static spark.Spark.*;
2
3 public class MyHelloWorld {
4 public static void main(String[] args) {
5 get("/sayhello", (request, response) -> "Hello Reader");
6 }
7 }

That's it! Line one, spark.Spark.*, as indicated in the preceding code snippet, does the magic. By using CURL (curl http://localhost:4567/sayhello), we would visualize the following request and response as output for the previous code:

Request: 
 
GET http://localhost:4567/sayhello 
 
Response: 
 
Hello Reader 
 

As we can see in the preceding snippet, curl hits the application, so the lambda function of Spark.* fires and the client (curl in this case) gets the output of the static lambda function. It's not just a simple hello world API; we can write complex RESTful APIs with Spark as it supports a variety of functions, such as query maps, cookies and sessions, filters, redirects, exception and error handlings, and views and templates.