The Java 21 update

We really needed this one? | Jun 23, 2023

YouTube just recommended me this video: https://www.youtube.com/watch?v=ZibsO2doQjU

tl;dr Java is simplifying the way you declare your program’s entry point.

What used to look like this:

class Program {
    public static void main(String[] args) {
        System.out.println("Hello World");
    }
}

Starting from Java 21 can be simplified to:

void main() {
    System.out.println("Hello World");
}

According to the video, it makes Java easier for beginners:

  • You no longer need to define a class or know what a class is

  • You no longer forced to declare your method public or specify static storage class

  • String[] argument list is no longer mandatory for the main method

Sounds great, isn’t it? Well, not for me. I wrote my very first programs in GW-BASIC, and later QBasic, learning the very basic foundations of programming:

  • Statements

  • Control statements, conditions

  • Variables

  • Loops

  • Input/Output

The Java example above still requires you to explain:

  • What is a function?

  • What void means

  • What is an argument list?

  • What is a code block

  • What are System, out and why are those dots there

  • What is a semicolon?

It’s not that complicated, your beginner can just learn that all programs start with void main() { and ends with }. Easy rules. I learned the same when moving to Turbo Pascal:

  • My programs started with uses Crt

  • All my statements gone between begin and end

  • All statements are closed with a semicolon

Easy rules, a 10-year old boy (me) was able to learn it very quickly. It took me years to discover units other than Crt (Dos, Graph, etc.), learn to organize my code into procedures, functions and even units and classes. None of those were needed. I did not need these for learning about read and write operations, for, while, repeat/until loops, variables, if .. then .. else conditions.

Still, I don’t understand why Java 21 wants you to declare that main function. Check C#:

System.Console.WriteLine("Hello, World!");

Or Swift:

print("Hello, World!")

Or Kotlin (Script):

println("Hello, World!")

Take a breath. I don’t even understand, why on Earth anyone would start to learn programming in Java. There are just better tools for that. Python, Swift or Kotlin, Groovy if you want to stick to JVM.

Professional programmers and authors of complex application would gain nothing. Removing the class declaration of the entry point of the app? Who cares. I barely see that source file anyway in our application.

There is another viable use case for these script-like Java programs: tools. But then again:

  • Why can’t omit the function declaration too?

  • Why would I wait to spin up a JVM, wait for my program to compile and execute instead of writing the whole thing in an environment that is more appropriate for tooling, like shell scripts or Python?

Don’t get me wrong, Java 21 is coming with important updates too. I just don’t like the idea how they want to make Java easier to approach for students. On one hand, I feel it unnecessary as the “ceremony” required to write a hello world can be learned quickly and also helps you ask further questions about Java programming. On the other hand: if you really want to simplify, this is just not enough.