RFR: 8344706: Compiler Implementation of Compact Source Files and Instance Main Methods

[Luca Kellermann]

On Fri, 4 Apr 2025 07:20:23 GMT, Jan Lahoda <jlahoda at openjdk.org> wrote:

> This is a PR that implements JEP: Compact Source Files and Instance Main Methods. Changes include:
> - `java.io.IO` moved to `java.lang.IO`, and no longer uses `System.console()` to implement the methods (thanks to @stuart-marks)
> - `java. ... .IO` is no longer automatically imported in any compilation unit
> - the feature is finalized (i.e. no longer requires `--enable-preview`)

src/java.base/share/classes/java/lang/IO.java line 122:

> 120:     public static void print(Object obj) {
> 121:         System.out.print(obj);
> 122:         System.out.flush();

Is it worth using a local variable to avoid calling `print` and `flush` on different streams in case `System.out` is reassigned in between?


var out = System.out;
out.print(obj);
out.flush();

src/java.base/share/classes/java/lang/IO.java line 147:

> 145:         } catch (IOException ioe) {
> 146:             throw new IOError(ioe);
> 147:         }

Was `UncheckedIOException` considered? It might be better for beginners to learn throwing exceptions instead of errors.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24438#discussion_r2029603325
PR Review Comment: https://git.openjdk.org/jdk/pull/24438#discussion_r2029604846