asmhatre/javademos
1
0
Fork 0
Code Actions Activity

Java 27 and 26: runnable demos and captured output for every JEP, plus version lanes

Browse Source 
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01B38FGKKam5SCGgwgduVAh3
This commit is contained in:
asmhatre
2026-09-21 15:08:50 +00:00
committed by Claude
co-authored by Claude Sonnet 5
commit f59c1de96d
152 changed files with 5049 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
docs/07-structured-concurrency.md
+27
View File
@@ -0,0 +1,27 @@
# 7. Structured concurrency (JEP 533, seventh preview)
Prev: [6. Lazy constants](06-lazy-constants.md) &middot; Next: [8. PEM](08-pem-api.md)
Compile and run with `--enable-preview --release 27`. Source: [`StructuredDemo`](../jep-tour/src/StructuredDemo.java), transcript [21](output/21-structured.txt).
The 27 API, as exercised:
```java
try (var scope = StructuredTaskScope.open(Joiner.<String>allSuccessfulOrThrow())) {
scope.fork(StructuredDemo::fetchPrice);
scope.fork(StructuredDemo::fetchStock);
List<String> results = scope.join(); // [price=42, stock=7], in fork order
}
```
* A failing subtask makes `join()` throw `ExecutionException` with the original as its cause.
* **New in 27:** `StructuredTaskScope` and `Joiner` gained a third type parameter, the exception `join()` throws. `Joiner.<String, OrderFailed>allSuccessfulOrThrow(OrderFailed::new)` makes `join()` throw *your* type.
* A timeout is a scope option (`cfg -> cfg.withTimeout(Duration.ofMillis(100))`) and surfaces as `CancelledByTimeoutException`.
## What broke from 26
[`StructuredScope26.java`](../jep-tour/src/broken/StructuredScope26.java) compiles on 26 and fails on 27 with three errors ([20-broken-structuredscope26.txt](output/20-broken-structuredscope26.txt)):
`wrong number of type arguments; required 3`, and `FailedException` / `TimeoutException` no longer exist as nested classes
([51](output/51-api-diff-26-to-27.txt): removed `StructuredTaskScope$FailedException`, `$TimeoutException`; added `$CancelledByTimeoutException`).
Prev: [6. Lazy constants](06-lazy-constants.md) &middot; Next: [8. PEM](08-pem-api.md)