Downgrade to Java 21 due to raphw/byte-buddy#1609 bug

pom.xml

@@ -10,8 +10,8 @@
     <description>Comparing Project Reactor vs Loom and getting them to work together</description>
 
     <properties>
-        <maven.compiler.source>22</maven.compiler.source>
-        <maven.compiler.target>22</maven.compiler.target>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <blockhound.version>1.0.8.RELEASE</blockhound.version>
         <exec.mainClass>org.addario.ReactiveLoom</exec.mainClass>
@@ -73,6 +73,7 @@
                         <compilerArgs>
                             <arg>--enable-preview</arg>
                             <arg>-XX:+EnableDynamicAgentLoading</arg>
+                            <arg>-XX:+AllowRedefinitionToAddDeleteMethods</arg>
                         </compilerArgs>
                     </configuration>
                 </plugin>

src/main/java/org/addario/ReactiveLoom.java

@@ -1,7 +1,7 @@
 package org.addario;
 
-import reactor.tools.agent.ReactorDebugAgent;
 import reactor.blockhound.BlockHound;
+import reactor.tools.agent.ReactorDebugAgent;
 
 import java.io.File;
 import java.util.UUID;
@@ -10,11 +10,11 @@ public class ReactiveLoom {
     public static void main(String[] args) throws InterruptedException {
         var quantity = 2_000_000; // Generating 2 million payment records should take around 10 seconds and will use about 3.9 GB of memory
         var batchSize = 100_000; // quantity / batchSize = how many groups of payments to process in parallel
-        var fileName = STR."\{UUID.randomUUID().toString()}.txt"; // Using Java 22 preview features so must be compiled/run with --enable-preview
+        var fileName = STR."\{UUID.randomUUID().toString()}.txt"; // Using Java 21 preview features so must be compiled/run with --enable-preview
         var file = new File(fileName); // A file with 2 million records will take around 3.3 GB
-        System.setProperty("reactor.schedulers.defaultBoundedElasticOnVirtualThreads", "true");
+        System.setProperty("reactor.schedulers.defaultBoundedElasticOnVirtualThreads", "true"); // Use virtual threads (projet Loom) in bounded elastic scheduler
 
-        ReactorDebugAgent.init(); // Dev friendly reactor stack traces
+        ReactorDebugAgent.init(); // Dev friendly reactive stack traces
         BlockHound.install(); // Detect and throw on blocking calls from non-blocking threads
 
         var paymentsList = TimedExecution.createPaymentsList(quantity);