Structure Concurrency Examples

This repository contains several examples for "Structured Concurrency", a feature described in JEP 453 and available in Java 21 as a preview feature.

I use these examples in my presentations on structured concurrency.

Java 21 IDE Support

IntelliJ IDEA supports Java 21 as of version 2023.2.2. As long as this version is not yet released, you can install the release candidate via the JetBrains Toolbox App by going into the IntelliJ IDEA settings and activating the "Early Access Program".

Compile and Run the Demos From the Command Line

You can also compile the application manually like this:

javac --enable-preview --source 21 -d target/classes src/main/java/eu/happycoders/structuredconcurrency/util/*.java src/main/java/eu/happycoders/structuredconcurrency/demo1_invoice/model/*.java src/main/java/eu/happycoders/structuredconcurrency/demo1_invoice/service/*.java src/main/java/eu/happycoders/structuredconcurrency/demo1_invoice/*.java src/main/java/eu/happycoders/structuredconcurrency/demo2_address/model/*.java src/main/java/eu/happycoders/structuredconcurrency/demo2_address/service/*.java src/main/java/eu/happycoders/structuredconcurrency/demo2_address/*.java src/main/java/eu/happycoders/structuredconcurrency/demo3_suppliers/model/*.java src/main/java/eu/happycoders/structuredconcurrency/demo3_suppliers/service/*.java src/main/java/eu/happycoders/structuredconcurrency/demo3_suppliers/*.java

And then run the three demos like this:

java -cp target/classes eu.happycoders.structuredconcurrency/demo1_invoice/InvoiceGenerator3_ThreadPool
java -cp target/classes --enable-preview eu.happycoders.structuredconcurrency/demo1_invoice/InvoiceGenerator5_StructuredTaskScope
java -cp target/classes --enable-preview eu.happycoders.structuredconcurrency/demo1_invoice/InvoiceGenerator6_ShutdownOnFailure
java -cp target/classes --enable-preview eu.happycoders.structuredconcurrency/demo2_address/AddressVerification2_ShutdownOnSuccess
java -cp target/classes --enable-preview eu.happycoders.structuredconcurrency/demo3_suppliers/SupplierDeliveryTimeCheck2_StructuredTaskScope
java -cp target/classes --enable-preview eu.happycoders.structuredconcurrency/demo3_suppliers/SupplierDeliveryTimeCheck3_NestedStructuredTaskScope
java -cp target/classes --enable-preview eu.happycoders.structuredconcurrency/demo3_suppliers/SupplierDeliveryTimeCheck4_NestedStructuredTaskScopeUsingScopedValue

Java Downloads

You can download Java 21 from here: https://jdk.java.net/21/

To install multiple Java versions on Linux or macOS, I recommend using SDKMAN!

To install multiple Java versions on Windows, have a look at this tutorial: How to Change Java Versions in Windows

Other Java 21 Examples

You might also find these GitHub repositories interesting:

Virtual Threads:

• https://github.com/SvenWoltmann/virtual-threads
• https://github.com/SvenWoltmann/virtual-threads-quarkus
• https://github.com/SvenWoltmann/virtual-threads-spring

Scoped Values:

• https://github.com/SvenWoltmann/scoped-values

Pattern Matching for Switch:

• https://github.com/SvenWoltmann/pattern-matching-for-switch