I think it is important to be able to determine the root cause of a problem first. Do students find difficult to write "public static void main(String[] args)" or do they find difficulty understanding the concepts of a public method, a static method, a void method? Perhaps then we should focus on teaching these concepts, which are essential to java, first, instead of undermining the core of the language and the platform.
Neither "goals" nor "summary" can explain away why this can solve the problem this JEP purports to solve.
> Perhaps then we should focus on teaching these concepts, which are essential to java, first.
As the JEP explains, this change does make the concepts of classes and access modifiers easier to teach by allowing the teacher to postpone their introduction to a point in time when they're actually useful and can be understood. Access control, static, and class declarations are only meaningful once you have other classes and/or objects interacting with your code. We don't want to force teachers to teach programming in the large early because many of them told us they don't do that anyway.
> instead of undermining the core of the language and the platform
The syntax and concepts of anonymous classes are unchanged. Providing an unnamed class, implicitly, when a class isn't needed is consistent with how we already provide an unnamed package and an unnamed module implicitly when they're not needed.
It sounds like you haven't taught or taken an intro to programming course using Java before.
In that situation, instructors might spend weeks trying to get their students to understand variables or control flow concepts. Visibility may be a core concern for you, as a (presumably) professional Java programmer, but it's not at all to programming novices.
This particular problem, in my opinion, has a much simpler solution: a special educational environment. A sort of mini-IDE where two things happen:
1. code written by a student gets inserted into a top-level class's main() method (has to be smart enough to deal with imports, inner classes etc.)
2. the top level class might declar certain utility functions such as print() instead of System.out.println(), and possibly others.
Bingo. No need to mess with something that works just fine for 99.99% of the professional users.
edit, in response to @crummy (as we reached the maximum depth it seems):
Some people commented that it might be beneficial to delay introduction of more complex concepts until the basic ones are digested. So hiding the class/main method would help with that (similar to jshell, I might add). And keep in mid this is an IDE and not java-lite.
Such an environment already exists, and the JEP rejects it as an option:
> Evolving a batch of working declarations in JShell into a real Java program leads to a non-idiomatic style of code because it declares each method, class, and variable as static... it is not the on-ramp programming model we are looking for.
> What I really dislike about this JEP is not only that it tries to solve the educational problem in a worst possible manner (my opinion), but it also risks creating a generation of students who don't really understand the fundamental concepts that allow us to write reliable code.
How would your special IDE/forked Java-lite prevent creating a generation of students who don't really understand the fundamental concepts that allow us to write reliable code?
The problem is when you sit down to teach the beginner, all the boilerplate clutter forces you to either A) teach them the magic incantation to be unquestionably written before they start writing any code, or B) you explain everything before getting into any real programming.
Both suck. In the first case, students are torn away from the mode of thinking that programming thrives in: that everything is made up of simple, understandable pieces, that can be built up into complex solutions. It ends up serving as a trap for the very kind of inquisitive student that is equipped to succeed in programming. In the second case, everyone's bored to tears, and you can be assured that your entire class will be hopelessly lost before they write their first line of code. It's a bad time all around.
Basically, programming wants to be built up with the following concepts, in order:
1. Algorithmic Thinking (solutions can be representing as a series of simple steps)
2. Structured Syntax (these steps can be represented as structured text)
3. Symbolic Reasoning (types, variables, arrays)
4. Control Flow (loops, conditionals)
5. Functions
6. Higher Structures (classes, objects, etc)
Python, IMO, is pretty good pedagogical tool in this regard
print("Hello World")
"We want our computer to display to us (or 'print' in software terms) the phrase 'Hello World'. Python provides us with a built-in way to do so: the "print" function. In the majority of programming languages, we express a call to a function as a command, followed by its inputs (or 'arguments') contained within parentheses. As our one and only argument, we provide what we want printed, in this case the text "Hello World". By wrapping this text in quotes, we can tell the language that we intend this text to be interpreted as a chunk of literal text, called a 'String' rather than as a variable or other symbol for the language."
In contrast, explaining everything going on in the equivalent Java
public class MyFirstClass {
public static void main(String[] args){
System.out.println("Hello World");
}
}
would take more text than I'm willing to hammer into a HN comment, but to be explained to a complete beginner would likely involve skipping, but promising to explain later: classes, functions, "public", "static", "void", command line arguments, and the uniquely weird "System.out", followed by a similar explanation to the Python example, with the added "we end each step with a semicolon".
Please see my response to @pgwhalen. In short, the problem has, I think, a much simpler solution.
What I really dislike about this JEP is not only that it tries to solve the educational problem in a worst possible manner (my opinion), but it also risks creating a generation of students who don't really understand the fundamental concepts that allow us to write reliable code.
Perhaps we need to start teaching basic programming with BASIC instead, and graduate to a more complicated platform once the basic concepts have been understood.
My personal opinion on it is that Java's simply a bad first language, and over-taught in schools. It has a lot of language-specific baggage that it thrusts upon you immediately on first use. My preferred first (university-level) language is Racket, because it's got incredibly simple syntax as a LISP, it's radically batteries-included giving a good sandbox to play in, and segues into CS-theory type stuff pretty damn well. It also has the added bonus of minimizing the impact on the subset of the class with non-trivial programming experience, who otherwise can easily get bored hearing stuff they know already, stop paying attention because they assume they know everything already, and then wash out when the real CS-heavy stuff hits.
But a lot of "universities" treat their "CS" programs as glorified trade schools, and want to focus exclusively on industry-applicable languages, and land on Java because Oracle had a great outreach program. Like it or not, many students will be starting their programming journey in Java, and not fucking it up is probably a good idea.
My approach would have been pretty similar to their listed alternative under "Interpret code units as static members", but that probably comes down to differences over the importance of Object-Oriented principals in beginner programming pedagogy.
Barring that, this proposal really isn't bad. It doesn't break existing code, it does its job well enough. I would have liked there to be support for inline subclasses that can be called from within the same anonymous class environment, but I can see how that would create ambiguity with existing code.
I think Java is a fine first language - it has a strongly typed, static runtime with good cross platform support, and stellar backwards compatibility (meaning that you can use decade old code samples as well).
The often touted alternative starting language is C and python, and I believe Java is better than both — C’s mentioned advantage is “learning low level details”, but I don’t see it as necessary, plus C can fail at runtime (or worse, at *some runtime on someone else’s machine) in completely cryptic ways, you may not even realize your program is incorrect until you submit an assignment. I have seen even very smart students be puzzled by it. Also, pointers can be learned afterwards easily, I don’t see it problematic at all.
Python’s problem comes mostly from its dynamically typed nature, it is very hard for new programmers to reason about the runtime state of programs, and why might have it failed on the nth cycle of this loop.
Java is a great in-between. It is not perfect (for example arrays having special syntax is not ideal), but not bad and it being an industry language is just a plus.
> I would have liked there to be support for inline subclasses that can be called from within the same anonymous class environment, but I can see how that would create ambiguity with existing code.
Not sure what you mean by "inline subclasses", but an anonymous main class can contain class declarations -- just as classes, named or anonymous can today. This file would be a complete legal program:
record Foo(int x, int y) {}
class Bar { static void print(Foo f) { System.out.println(f); } }
void main() {
Bar.print(makeFoo());
}
Foo makeFoo() { return new Foo(3, 4); }
Ah, in that case I take that back. I definitely thought you needed to be able to reference the parent class in order to call (classes defined within other classes, can't remember the nomenclature).
There's no need to do that from within the class. It all works just as it would in an anonymous class today. This code, that employs an anonymous class, is valid Java today (you can paste it into jshell):
new Object() {
record Foo(int x, int y) {}
class Bar { static void print(Foo f) { System.out.println(f); } }
void main() {
Bar.print(makeFoo());
}
Foo makeFoo() { return new Foo(3, 4); }
}.main();
This JEP merely brings together two existing ideas in Java:
1. Anonymous classes
2. Unnamed instances of programming-in-the-large concepts are implicitly provided for you (today this is the case only for packages and modules).
There are no new changes or restrictions to Java syntax in the body of the anonymous class.
Why would it create a generation of students who don’t understand the fundamentals? You will have to use all the language features for anything more complex, it is only for the earlier lessons.
I think it is important to be able to determine the root cause of a problem first. Do students find difficult to write "public static void main(String[] args)" or do they find difficulty understanding the concepts of a public method, a static method, a void method? Perhaps then we should focus on teaching these concepts, which are essential to java, first, instead of undermining the core of the language and the platform.
Neither "goals" nor "summary" can explain away why this can solve the problem this JEP purports to solve.
This is my opinion, of course.