this post was submitted on 13 Nov 2024
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Anon tries programming in Java (lemmy.world)
submitted 1 day ago by [email protected] to c/[email protected]
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[–] [email protected] 25 points 1 day ago (5 children)

Hello World

30 minutes of boilerplate

writing imports

$ cat <<EOF > Hello.java
public class Hello {
  public static void main(String args[]) {
    System.out.println("Hello world!");
  }
}
EOF
$ java Hello.java
Hello world!

ok

[–] [email protected] 6 points 21 hours ago (3 children)

This is getting a little better nowadays.

> cat Hello.java
void main() {
    System.out.println("Hello, World!");
}
> java --enable-preview Hello.java
Hello, World!

Things to notice:

  1. No compilation step.
  2. No class declaration.
  3. Main method is not public static
  4. No String[] args.

This still uses preview features though. However, like you demonstrated already, compilation is no longer a required step for simplistic programs like this.

[–] [email protected] 1 points 7 hours ago

System.base.stuff.output.out.printfunctions.println

Or so it felt every time you wanted to dump something into the console...

[–] [email protected] 1 points 13 hours ago* (last edited 13 hours ago) (1 children)

Main method is not public static

It must be somewhere under the hood. Otherwise, it wont be callable and it would require an instance of an object to call. Unless the object here is the Java environment?

No String[] args

They are just optional I'm sure, like C and C++. You still need them to read command line arguments.

All in all, these syntax improvements are welcome. I already moved on to Kotlin for Android development though.

[–] [email protected] 1 points 12 hours ago* (last edited 12 hours ago) (1 children)

Main method is not public static

It must be somewhere under the hood. Otherwise, it wont be callable and it would require an instance of an object to call. Unless the object here is the Java environment?

No. From JEP-445:

If an unnamed class has an instance main method rather than a static main method then launching it is equivalent to the following, which employs the existing anonymous class declaration construct:

new Object() {
    // the unnamed class's body
}.main();

No String[] args

They are just optional I'm sure, like C and C++. You still need them to read command line arguments.

Without the preview feature enabled, it is not an optional part of the method signature. It specifically looks for a main(String[]) signature.

[–] [email protected] 0 points 11 hours ago (1 children)

I am not in the mood to read a technical document, but I don’t think the resulting binary/byte code should be different between the two “hello world” programs. But then again, why not?

Without the preview feature enabled, it is not an optional part of the method signature. It specifically looks for a main(String[]) signature.

Ah ha! So that’s what’s going on here. They almost got it right. They had the potential to make a lot of the boilerplate optional or implicit under relevant circumstances, but instead the language has two explicit switchable modes.

Can I write a Java application in “preview feature”?

[–] [email protected] 4 points 10 hours ago* (last edited 10 hours ago) (1 children)

I mentioned this uses preview features twice in the first comment regarding this, so I don't know why you're "ah ha"ing. Also you don't need to read the technical document, I've quoted the entirety of the relevant text. I provided it as a citation.

You seem confused about preview features. It's not a switchable mode to reduce boiler plate. I find the name very clear, but here is more information. From JEP-12

A preview feature is a new feature of the Java language, Java Virtual Machine, or Java SE API that is fully specified, fully implemented, and yet impermanent. It is available in a JDK feature release to provoke developer feedback based on real world use; this may lead to it becoming permanent in a future Java SE Platform.

As an example, JDK 17 added pattern matching for switch statements as a preview, and by JDK 21 it was added as a full fledged feature that doesn't require usage of the enable preview flag. Presumably in some future release of Java this feature will not require the usage of a flag.

[–] [email protected] 1 points 10 hours ago* (last edited 10 hours ago) (1 children)

It is pretty late for me. Sorry. And thank you for your patience. Repeating it three times helped.

I will be interesting to find out if the resulting binary is the same or not and what’s possible once it matured.

[–] [email protected] 2 points 10 hours ago

Yes, because it's genuinely not a static method. It's an instance method. Also the signature is different. It's not some sort of mere syntactic trick that translates void main() to public static void main(String[] args).

[–] [email protected] 3 points 18 hours ago* (last edited 18 hours ago) (1 children)

Microsoft Java is a one-liner these days.

> cat program.cs
Console.WriteLine("Hello, World!");
> dotnet run
Hello, World!
[–] [email protected] 17 points 22 hours ago* (last edited 22 hours ago) (1 children)

Python:

print("Hello world!")
[–] [email protected] 11 points 22 hours ago* (last edited 22 hours ago) (2 children)

C:

#include <stdio.h>

int main() {
    printf("Hello World!");
    return(0);
}

EDIT: POSIX-compatible shell:

echo "Hello World!"
[–] [email protected] 4 points 11 hours ago (1 children)

PHP:

Hello World!
[–] [email protected] 2 points 8 hours ago

Rust:

Still fighting the burrito check fil er
[–] [email protected] 3 points 22 hours ago* (last edited 22 hours ago) (1 children)

Python2 is only one character longer:

print "Hello world!"

And you get proper data types too.

[–] [email protected] 2 points 21 hours ago

Shell is only meant for duct tape scripts, you know to tie two regular compiled programs together

[–] [email protected] 3 points 23 hours ago* (last edited 23 hours ago)

I got the impression they skipped the hello world cause it was too easy and they wanted to get right to writing their app, so they moved on to more advanced stuff without having a real grasp of the basics

[–] [email protected] 4 points 1 day ago

He types REALLY slow.

[–] [email protected] 21 points 1 day ago (4 children)

Welcome to java, we have a couple unconventional ways of doing things, but overall I'm like every other mainstream oo language.

People: AHH! Scary!

Welcome to python. your knowledge of me wont help you elsewhere as my syntax is purposefully obtuse and unique. Forget about semicolons, one missed space and your code is as worthless as you after learning this language.

People: Hello based department

[–] [email protected] 3 points 21 hours ago* (last edited 21 hours ago)

**kwargs

"No, I don't use type annotations because they don't actually do anything. In fact I purposefully give this parameter different types for different behaviors. How is that confusing?"

[–] [email protected] 9 points 23 hours ago (1 children)

Oh my god I got fucked by a python script once because of a single space. It took forever to figure out what went wrong

[–] [email protected] 2 points 13 hours ago* (last edited 13 hours ago)

I refuse to code in Python without a really good IDE and linting like PyCharm. When using PyCharm it's very rare I have issues like this, because it catches them in one way or another, but I notice it catches those kinds of issues a lot when I'm coding soooooooo....

I have also setup the IDE to specifically color code comments like

' # End If and ' # Next

in the same style as their beginning statements as I find it much easier to visually scam through code when they are present.

[–] [email protected] 3 points 1 day ago

Python has its drawbacks but it also has a pretty useful standard library so as a language for small scripts, one can do much worse

[–] [email protected] 2 points 1 day ago* (last edited 1 day ago)

It is possible to dislike both. For me SmallTalk-like languages are peak. Message passing for life!