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<blockquote type="cite" cite="mid:06823323-6214-438A-80A7-184310F01C55@oracle.com">
<div class="">(1) Instead of having a magic “unnamed” class, which
has bizarre properties such as not having a constructor (or at
least not a constructor you can mention in a `new` expression),
only to then require a second magic rule about what you put in
the command line “java …”, why not simply use the much more
obvious rule that if a compilation unit doesn't have a class
header, then a class header is _supplied_ by the compiler, and
the name of the class is taken from the filename of the
compilation unit?</div>
</blockquote>
<br>
The implementation does something like this, which is almost a
forced move due to the vagaries of the various extralinguistic rules
like "Foo.class should not contain a class other than Foo" (enforced
by the class loader.) So indeed, if Foo.java contains an "unnamed"
class, Foo.class will contain a class called "Foo". <br>
<br>
The main difference (if there is one) is the meaning of the name Foo
in the body of the class. This relates to another "unnamed" JEP in
flight, which is "unnamed variables", such as:<br>
<br>
var _ = mySideEffects();<br>
<br>
Here, _ refers to a variable whose name is not entered into the
symbol table, and is therefore write-once, read-none. The proposal
herein for unnamed classes treats the class name the same way.
(Full disclosure: since there is a Foo.class with a class called Foo
in it, it is hard to stop _other_ classes from instantiating it.)<br>
<br>
What you are suggesting is to instead take that
extralinguistically-derived name and make it official. This reduces
some of the restrictions (you can have constructors) but seems like
it creates new ghosts from different machines, since now there is a
name that has meaning in the language but which didn't come from any
Java source code. <br>
<br>
<blockquote type="cite" cite="mid:06823323-6214-438A-80A7-184310F01C55@oracle.com">
<div class="">(2) Instead of complicating the Java launch
protocol, why not leave it along, and instead use the existing
mechanism of “in situation X, if the user fails to provide
method Y, the compiler will provide a definition automatically”?
Specifically, in a compilation unit named Foo.java for which a
class header has to be provided automatically, if a method with
signature “main()” is present but no static method with
signature “main(String[])” is present, then a static method with
signature “main(String[])” is automatically provided by the
compiler.</div>
</blockquote>
<br>
Saying that you can only use these two mechanisms together seems a
sharp edge that users will get caught on. The two simplifications
are orthogonal; there is "instance main" and there is "low ceremony
classes", but coupling the two in this way means you have to give up
one if you don't use the other. <br>
<br>
However, your "if you don't provide..." approach is an entirely
valid way to implement "instance main" -- by injecting additional
methods into the compiled class rather than modifying the launcher.
It would be specified slightly differently (since it is also
reflectively visible) but that's OK. <br>
<br>
<blockquote type="cite" cite="mid:06823323-6214-438A-80A7-184310F01C55@oracle.com">(3)
Instead of speaking of automatic imports, speak of the compiler
automatically providing certain import statements if the
compilation unit doesn’t have a class header.
</blockquote>
<br>
If we did this, when a class "graduates" from a low-ceremony class
to a full class, then they'd have to go back and fix up all the
println calls, and similarly it would put users in a position of
"you can have ceremony reduction X, but only if you qualify for
ceremony reduction Y." It is surely a weaker argument that
`println` needs to be effectively global, but after having
programmed without saying "System.out" in front of println for only
a few weeks, one already feels like going back is a punishment.
(Its small, I know, but in some situations you type it a lot.) We
have also seen the need for automatic imports elsewhere, such as in
JEP 430, where a feature of the language carries with it a static
member (the STR and FMT template processors), and requiring an
explicit static import seems burdensome. <br>
<br>
Taken together, coupling "instance main" and "auto static imports"
to "no class header" means that we have created a "beginners
dialect" which is different, and which has to be unlearned and
undone as soon as a class graduates. I would prefer to have these
be orthogonal features to the extent possible. <br>
<br>
<blockquote type="cite" cite="mid:06823323-6214-438A-80A7-184310F01C55@oracle.com">
<div class="">That way _everything_ (the name of class when a
class header is not provided, the behavior when you write
variously abbreviated definitions of method `main`, and the
automatic importation of certain libraries) can be explained in
terms of source-code rewrites that the programmer can do once
the programmer learns enough about more advanced features.</div>
<div class=""><br class="">
</div>
<div class="">—Guy</div>
<div class=""><br class="">
</div>
<div class="">
<div class="">
<div><br class="">
<blockquote type="cite" class="">
<div class="">On Sep 28, 2022, at 1:57 PM, Brian Goetz
<<a href="mailto:brian.goetz@oracle.com" class="moz-txt-link-freetext" moz-do-not-send="true">brian.goetz@oracle.com</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div class=""><font class="" size="4"><font class="" face="monospace">At various points, we've explored
the question of which program elements are most
and least helpful for students first learning
Java. After considering a number of alternatives
over the years, I have a simple proposal for
smoothing the "on ramp" to Java programming, while
not creating new things to unlearn.
<br class="">
<br class="">
Markdown source is below, HTML will appear soon
at: <br class="">
<br class="">
<a class="moz-txt-link-freetext" href="https://openjdk.org/projects/amber/design-notes/on-ramp" moz-do-not-send="true">
https://openjdk.org/projects/amber/design-notes/on-ramp</a><br class="">
<br class="">
<br class="">
# Paving the on-ramp<br class="">
<br class="">
Java is one of the most widely taught programming
languages in the world. Tens<br class="">
of thousands of educators find that the imperative
core of the language combined<br class="">
with a straightforward standard library is a
foundation that students can<br class="">
comfortably learn on. Choosing Java gives
educators many degrees of freedom:<br class="">
they can situate students in `jshell` or Notepad
or a full-fledged IDE; they can<br class="">
teach imperative, object-oriented, functional, or
hybrid programming styles; and<br class="">
they can easily find libraries to interact with
external data and services. <br class="">
<br class="">
No language is perfect, and one of the most common
complaints about Java is that<br class="">
it is "too verbose" or has "too much ceremony."
And unfortunately, Java imposes<br class="">
its heaviest ceremony on those first learning the
language, who need and<br class="">
appreciate it the least. The declaration of a
class and the incantation of<br class="">
`public static void main` is pure mystery to a
beginning programmer. While<br class="">
these incantations have principled origins and
serve a useful organizing purpose<br class="">
in larger programs, they have the effect of
placing obstacles in the path of<br class="">
_becoming_ Java programmers. Educators constantly
remind us of the litany of<br class="">
complexity that students have to confront on Day 1
of class -- when they really<br class="">
just want to write their first program. <br class="">
<br class="">
As an amusing demonstration of this, in her
JavaOne keynote appearance in 2019,<br class="">
[Aimee Lucido](<a class="moz-txt-link-freetext" href="https://www.youtube.com/watch?v=BkPPFiXUwYk" moz-do-not-send="true">https://www.youtube.com/watch?v=BkPPFiXUwYk</a>)
talked about when<br class="">
she learned to program in Java, and how her
teacher performed a rap song<br class="">
to help students memorize `"public static void
main"`. Our hats are off to<br class="">
creative educators everywhere for this kind of
dedication, but teachers<br class="">
shouldn't have to do this.<br class="">
<br class="">
Of course, advanced programmers complain about
ceremony too. We will never be<br class="">
able to satisfy programmers' insatiable appetite
for typing fewer keystrokes,<br class="">
and we shouldn't try, because the goal of
programming is to write programs that<br class="">
are easy to read and are clearly correct, not
programs that were easy to type.<br class="">
But we can try to better align the ceremony
commensurate with the value it<br class="">
brings to a program -- and let simple programs be
expressed more simply. <br class="">
<br class="">
## Concept overload<br class="">
<br class="">
The classic "Hello World" program looks like this
in Java:<br class="">
<br class="">
```<br class="">
public class HelloWorld { <br class="">
public static void main(String[] args) { <br class="">
System.out.println("Hello World");<br class="">
}<br class="">
}<br class="">
```<br class="">
<br class="">
It may only be five lines, but those lines are
packed with concepts that are<br class="">
challenging to absorb without already having some
programming experience and<br class="">
familiarity with object orientation. Let's break
down the concepts a student<br class="">
confronts when writing their first Java program:<br class="">
<br class="">
- **public** (on the class). The `public`
accessibility level is relevant<br class="">
only when there is going to be cross-package
access; in a simple "Hello<br class="">
World" program, there is only one class, which
lives in the unnamed package.<br class="">
They haven't even written a one-line program
yet; the notion of access<br class="">
control -- keeping parts of a program from
accessing other parts of it -- is<br class="">
still way in their future.<br class="">
<br class="">
- **class**. Our student hasn't set out to
write a _class_, or model a<br class="">
complex system with objects; they want to
write a _program_. In Java, a<br class="">
program is just a `main` method in some class,
but at this point our student<br class="">
still has no idea what a class is or why they
want one.<br class="">
<br class="">
- **Methods**. Methods are of course a key
concept in Java, but the mechanics<br class="">
of methods -- parameters, return types, and
invocation -- are still<br class="">
unfamiliar, and the `main` method is invoked
magically from the `java`<br class="">
launcher rather than from explicit code. <br class="">
<br class="">
- **public** (again). Like the class, the
`main` method has to be public, but<br class="">
again this is only relevant when programs are
large enough to require<br class="">
packages to organize them. <br class="">
<br class="">
- **static**. The `main` method has to be
static, and at this point, students<br class="">
have no context for understanding what a
static method is or why they want<br class="">
one. Worse, the early exposure to `static`
methods will turn out to be a<br class="">
bad habit that must be later unlearned. Worse
still, the fact that the<br class="">
`main` method is `static` creates a seam
between `main` and other methods;<br class="">
either they must become `static` too, or the
`main` method must trampoline<br class="">
to some sort of "instance main" (more
ceremony!) And if we get this wrong,<br class="">
we get the dreaded and mystifying `"cannot be
referenced from a static<br class="">
context"` error.<br class="">
<br class="">
- **main**. The name `main` has special meaning
in a Java program, indicating<br class="">
the starting point of a program, but this
specialness hides behind being an<br class="">
ordinary method name. This may contribute to
the sense of "so many magic<br class="">
incantations."<br class="">
<br class="">
- **String[]**. The parameter to `main` is an
array of strings, which are the<br class="">
arguments that the `java` launcher collected
from the command line. But our<br class="">
first program -- likely our first dozen --
will not use command-line<br class="">
parameters. Requiring the `String[]` parameter
is, at this point, a mistake<br class="">
waiting to happen, and it will be a long time
until this parameter makes<br class="">
sense. Worse, educators may be tempted to
explain arrays at this point,<br class="">
which further increases the
time-to-first-program.<br class="">
<br class="">
- **System.out.println**. If you look closely
at this incantation, each<br class="">
element in the chain is a different thing --
`System` is a class (what's a<br class="">
class again?), `out` is a static field (what's
a field?), and `println` is<br class="">
an instance method. The only part the student
cares about right now is<br class="">
`println`; the rest of it is an incantation
that they do not yet understand<br class="">
in order to get at the behavior they want.<br class="">
<br class="">
That's a lot to explain to a student on the first
day of class. There's a good<br class="">
chance that by now, class is over and we haven't
written any programs yet, or<br class="">
the teacher has said "don't worry what this means,
you'll understand it later"<br class="">
six or eight times. Not only is this a lot of
_syntactic_ things to absorb, but<br class="">
each of those things appeals to a different
concept (class, method, package,<br class="">
return value, parameter, array, static, public,
etc) that the student doesn't<br class="">
have a framework for understanding yet. Each of
these will have an important<br class="">
role to play in larger programs, but so far, they
only contribute to "wow,<br class="">
programming is complicated." <br class="">
<br class="">
It won't be practical (or even desirable) to get
_all_ of these concepts out of<br class="">
the student's face on day 1, but we can do a lot
-- and focus on the ones that<br class="">
do the most to help beginners understand how
programs are constructed.<br class="">
<br class="">
## Goal: a smooth on-ramp<br class="">
<br class="">
As much as programmers like to rant about
ceremony, the real goal here is not<br class="">
mere ceremony reduction, but providing a graceful
_on ramp_ to Java programming.<br class="">
This on-ramp should be helpful to beginning
programmers by requiring only those<br class="">
concepts that a simple program needs. <br class="">
<br class="">
Not only should an on-ramp have a gradual slope
and offer enough acceleration<br class="">
distance to get onto the highway at the right
speed, but its direction must<br class="">
align with that of the highway. When a programmer
is ready to learn about more<br class="">
advanced concepts, they should not have to discard
what they've already learned,<br class="">
but instead easily see how the simple programs
they've already written<br class="">
generalize to more complicated ones, and both the
syntatic and conceptual<br class="">
transformation from "simple" to "full blown"
program should be straightforward<br class="">
and unintrusive. It is a definite non-goal to
create a "simplified dialect of<br class="">
Java for students".<br class="">
<br class="">
We identify three simplifications that should aid
both educators and students in<br class="">
navigating the on-ramp to Java, as well as being
generally useful to simple<br class="">
programs beyond the classroom as well:<br class="">
<br class="">
- A more tolerant launch protocol<br class="">
- Unnamed classes<br class="">
- Predefined static imports for the most critical
methods and fields<br class="">
<br class="">
## A more tolerant launch protocol<br class="">
<br class="">
The Java Language Specification has relatively
little to say about how Java<br class="">
"programs" get launched, other than saying that
there is some way to indicate<br class="">
which class is the initial class of a program (JLS
12.1.1) and that a public<br class="">
static method called `main` whose sole argument is
of type `String[]` and whose<br class="">
return is `void` constitutes the entry point of
the indicated class. <br class="">
<br class="">
We can eliminate much of the concept overload
simply by relaxing the<br class="">
interactions between a Java program and the `java`
launcher:<br class="">
<br class="">
- Relax the requirement that the class, and
`main` method, be public. Public<br class="">
accessibility is only relevant when access
crosses packages; simple programs<br class="">
live in the unnamed package, so cannot be
accessed from any other package<br class="">
anyway. For a program whose main class is in
the unnamed package, we can<br class="">
drop the requirement that the class or its
`main` method be public,<br class="">
effectively treating the `java` launcher as if
it too resided in the unnamed<br class="">
package.<br class="">
<br class="">
- Make the "args" parameter to `main` optional,
by allowing the `java` launcher to<br class="">
first look for a main method with the
traditional `main(String[])`<br class="">
signature, and then (if not found) for a main
method with no arguments.<br class="">
<br class="">
- Make the `static` modifier on `main` optional,
by allowing the `java` launcher to<br class="">
invoke an instance `main` method (of either
signature) by instantiating an<br class="">
instance using an accessible no-arg constructor
and then invoking the `main`<br class="">
method on it.<br class="">
<br class="">
This small set of changes to the launch protocol
strikes out five of the bullet<br class="">
points in the above list of concepts: public
(twice), static, method parameters,<br class="">
and `String[]`. <br class="">
<br class="">
At this point, our Hello World program is now:<br class="">
<br class="">
```<br class="">
class HelloWorld { <br class="">
void main() { <br class="">
System.out.println("Hello World");<br class="">
}<br class="">
}<br class="">
```<br class="">
<br class="">
It's not any shorter by line count, but we've
removed a lot of "horizontal<br class="">
noise" along with a number of concepts. Students
and educators will appreciate<br class="">
it, but advanced programmers are unlikely to be in
any hurry to make these<br class="">
implicit elements explicit either. <br class="">
<br class="">
Additionally, the notion of an "instance main" has
value well beyond the first<br class="">
day. Because excessive use of `static` is
considered a code smell, many<br class="">
educators encourage the pattern of "all the static
`main` method does is<br class="">
instantiate an instance and call an instance
`main` method" anyway. Formalizing<br class="">
the "instance main" protocol reduces a layer of
boilerplate in these cases, and<br class="">
defers the point at which we have to explain what
instance creation is -- and<br class="">
what `static` is. (Further, allowing the `main`
method to be an instance method<br class="">
means that it could be inherited from a
superclass, which is useful for simple<br class="">
frameworks such as test runners or service
frameworks.)<br class="">
<br class="">
## Unnamed classes<br class="">
<br class="">
In a simple program, the `class` declaration often
doesn't help either, because<br class="">
other classes (if there are any) are not going to
reference it by name, and we<br class="">
don't extend a superclass or implement any
interfaces. If we say an "unnamed<br class="">
class" consists of member declarations without a
class header, then our Hello<br class="">
World program becomes:<br class="">
<br class="">
```<br class="">
void main() { <br class="">
System.out.println("Hello World");<br class="">
}<br class="">
```<br class="">
<br class="">
Such source files can still have fields, methods,
and even nested classes, so<br class="">
that as a program evolves from a few statements to
needing some ancillary state<br class="">
or helper methods, these can be factored out of
the `main` method while still<br class="">
not yet requiring a full class declaration:<br class="">
<br class="">
```<br class="">
String greeting() { return "Hello World"; }<br class="">
<br class="">
void main() {<br class="">
System.out.println(greeting());<br class="">
}<br class="">
```<br class="">
<br class="">
This is where treating `main` as an instance
method really shines; the user has<br class="">
just declared two methods, and they can freely
call each other. Students need<br class="">
not confront the confusing distinction between
instance and static methods yet;<br class="">
indeed, if not forced to confront static members
on day 1, it might be a while<br class="">
before they do have to learn this distinction.
The fact that there is a<br class="">
receiver lurking in the background will come in
handy later, but right now is<br class="">
not bothering anybody.<br class="">
<br class="">
[JEP 330](<a class="moz-txt-link-freetext" href="https://openjdk.org/jeps/330" moz-do-not-send="true">https://openjdk.org/jeps/330</a>)
allows single-file programs to be<br class="">
launched directly without compilation; this
streamlined launcher pairs well with<br class="">
unnamed classes. <br class="">
<br class="">
## Predefined static imports<br class="">
<br class="">
The most important classes, such as `String` and
`Integer`, live in the<br class="">
`java.lang` package, which is automatically
on-demand imported into all<br class="">
compilation units; this is why we do not have to
`import java.lang.String` in<br class="">
every class. Static imports were not added until
Java 5, but no corresponding<br class="">
facility for automatic on-demand import of common
behavior was added at that<br class="">
time. Most programs, however, will want to do
console IO, and Java forces us to<br class="">
do this in a roundabout way -- through the static
`System.out` and `System.in`<br class="">
fields. Basic console input and output is a
reasonable candidate for<br class="">
auto-static import, as one or both are needed by
most simple programs. While<br class="">
these are currently instance methods accessed
through static fields, we can<br class="">
easily create static methods for `println` and
`readln` which are suitable for<br class="">
static import, and automatically import them. At
which point our first program<br class="">
is now down to:<br class="">
<br class="">
```<br class="">
void main() {<br class="">
println("Hello World");<br class="">
}<br class="">
```<br class="">
<br class="">
## Putting this all together<br class="">
<br class="">
We've discussed several simplifications:<br class="">
<br class="">
- Update the launcher protocol to make public,
static, and arguments optional<br class="">
for main methods, and for main methods to be
instance methods (when a<br class="">
no-argument constructor is available); <br class="">
- Make the class wrapper for "main classes"
optional (unnamed classes);<br class="">
- Automatically static import methods like
`println`<br class="">
<br class="">
which together whittle our long list of day-1
concepts down considerably. While<br class="">
this is still not as minimal as the minimal Python
or Ruby program -- statements<br class="">
must still live in a method -- the goal here is
not to win at "code golf". The<br class="">
goal is to ensure that concepts not needed by
simple programs need not appear in<br class="">
those programs, while at the same time not
encouraging habits that have to be<br class="">
unlearned as programs scale up. <br class="">
<br class="">
Each of these simplifications is individually
small and unintrusive, and each is<br class="">
independent of the others. And each embodies a
simple transformation that the<br class="">
author can easily manually reverse when it makes
sense to do so: elided<br class="">
modifiers and `main` arguments can be added back,
the class wrapper can be added<br class="">
back when the affordances of classes are needed
(supertypes, constructors), and<br class="">
the full qualifier of static-import can be added
back. And these reversals are<br class="">
independent of one another; they can done in any
combination or any order.<br class="">
<br class="">
This seems to meet the requirements of our
on-ramp; we've eliminated most of the<br class="">
day-1 ceremony elements without introducing new
concepts that need to be<br class="">
unlearned. The remaining concepts -- a method is a
container for statements, and<br class="">
a program is a Java source file with a `main`
method -- are easily understood in<br class="">
relation to their fully specified counterparts. <br class="">
<br class="">
## Alternatives<br class="">
<br class="">
Obviously, we've lived with the status quo for 25+
years, so we could continue<br class="">
to do so. There were other alternatives explored
as well; ultimately, each of<br class="">
these fell afoul of one of our goals.<br class="">
<br class="">
### Can't we go further?<br class="">
<br class="">
Fans of "code golf" -- of which there are many --
are surely right now trying to<br class="">
figure out how to eliminate the last little bit,
the `main` method, and allow<br class="">
statements to exist at the top-level of a
program. We deliberately stopped<br class="">
short of this because it offers little value
beyond the first few minutes, and<br class="">
even that small value quickly becomes something
that needs to be unlearned. <br class="">
<br class="">
The fundamental problem behind allowing such
"loose" statements is that<br class="">
variables can be declared inside both classes
(fields) and methods (local<br class="">
variables), and they share the same syntactic
production but not the same<br class="">
semantics. So it is unclear (to both compilers
and humans) whether a "loose"<br class="">
variable would be a local or a field. If we tried
to adopt some sort of simple<br class="">
heuristic to collapse this ambiguity (e.g.,
whether it precedes or follows the<br class="">
first statement), that may satisfy the compiler,
but now simple refactorings<br class="">
might subtly change the meaning of the program,
and we'd be replacing the<br class="">
explicit syntactic overhead of `void main()` with
an invisible "line" in the<br class="">
program that subtly affects semantics, and a new
subtle rule about the meaning<br class="">
of variable declarations that applies only to
unnamed classes. This doesn't<br class="">
help students, nor is this particularly helpful
for all but the most trivial<br class="">
programs. It quickly becomes a crutch to be
discarded and unlearned, which<br class="">
falls afoul of our "on ramp" goals. Of all the
concepts on our list, "methods"<br class="">
and "a program is specified by a main method" seem
the ones that are most worth<br class="">
asking students to learn early.<br class="">
<br class="">
### Why not "just" use `jshell`? <br class="">
<br class="">
While JShell is a great interactive tool, leaning
too heavily on it as an onramp<br class="">
would fall afoul of our goals. A JShell session
is not a program, but a<br class="">
sequence of code snippets. When we type
declarations into `jshell`, they are<br class="">
viewed as implicitly static members of some
unspecified class, with<br class="">
accessibility is ignored completely, and
statements execute in a context where<br class="">
all previous declarations are in scope. This is
convenient for experimentation<br class="">
-- the primary goal of `jshell` -- but not such a
great mental model for<br class="">
learning to write Java programs. Transforming a
batch of working declarations<br class="">
in `jshell` to a real Java program would not be
sufficiently simple or<br class="">
unintrusive, and would lead to a non-idiomatic
style of code, because the<br class="">
straightforward translation would have us
redeclaring each method, class, and<br class="">
variable declaration as `static`. Further, this
is probably not the direction<br class="">
we want to go when we scale up from a handful of
statements and declarations to<br class="">
a simple class -- we probably want to start using
classes as classes, not just<br class="">
as containers for static members. JShell is a
great tool for exploration and<br class="">
debugging, and we expect many educators will
continue to incorporate it into<br class="">
their curriculum, but is not the on-ramp
programming model we are looking for. <br class="">
<br class="">
### What about "always local"?<br class="">
<br class="">
One of the main tensions that `main` introduces is
that most class members are<br class="">
not `static`, but the `main` method is -- and that
forces programmers to<br class="">
confront the seam between static and non-static
members. JShell answers this<br class="">
with "make everything static". <br class="">
<br class="">
Another approach would be to "make everything
local" -- treat a simple program<br class="">
as being the "unwrapped" body of an implicit main
method. We already allow<br class="">
variables and classes to be declared local to a
method. We could add local<br class="">
methods (a useful feature in its own right) and
relax some of the asymmetries<br class="">
around nesting (again, an attractive cleanup), and
then treat a mix of<br class="">
declarations and statements without a class
wrapper as the body of an invisible<br class="">
`main` method. This seems an attractive model as
well -- at first.<br class="">
<br class="">
While the syntactic overhead of converting back to
full-blown classes -- wrap<br class="">
the whole thing in a `main` method and a `class`
declaration -- is far less<br class="">
intrusive than the transformation inherent in
`jshell`, this is still not an<br class="">
ideal on-ramp. Local variables interact with
local classes (and methods, when<br class="">
we have them) in a very different way than
instance fields do with instance<br class="">
methods and inner classes: their scopes are
different (no forward references),<br class="">
their initialization rules are different, and
captured local variables must be<br class="">
effectively final. This is a subtly different
programming model that would then<br class="">
have to be unlearned when scaling up to full
classes. Further, the result of<br class="">
this wrapping -- where everything is local to the
main method -- is also not<br class="">
"idiomatic Java". So while local methods may be
an attractive feature, they are<br class="">
similarly not the on-ramp we are looking for.<br class="">
<br class="">
<br class="">
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