[NO-TICKET] Use virtual threads

Author: pboos

openapi-validation-core/src/main/java/com/getyourguide/openapi/validation/core/OpenApiRequestValidator.java

@@ -14,26 +14,26 @@
 import java.net.URLDecoder;
 import java.nio.charset.StandardCharsets;
 import java.util.List;
+import java.util.concurrent.Executor;
 import java.util.concurrent.RejectedExecutionException;
-import java.util.concurrent.ThreadPoolExecutor;
 import javax.annotation.Nullable;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.http.client.utils.URLEncodedUtils;
 
 @Slf4j
 public class OpenApiRequestValidator {
-    private final ThreadPoolExecutor threadPoolExecutor;
+    private final Executor executor;
     private final OpenApiInteractionValidatorWrapper validator;
     private final ValidationReportToOpenApiViolationsMapper mapper;
 
     public OpenApiRequestValidator(
-        ThreadPoolExecutor threadPoolExecutor,
+        Executor executor,
         MetricsReporter metricsReporter,
         OpenApiInteractionValidatorWrapper validator,
         ValidationReportToOpenApiViolationsMapper mapper,
         OpenApiRequestValidationConfiguration configuration
     ) {
-        this.threadPoolExecutor = threadPoolExecutor;
+        this.executor = executor;
         this.validator = validator;
         this.mapper = mapper;
 
@@ -74,7 +74,7 @@ public void validateResponseObjectAsync(
 
     private void executeAsync(Runnable command) {
         try {
-            threadPoolExecutor.execute(command);
+            executor.execute(command);
         } catch (RejectedExecutionException ignored) {
             // ignored
         }

openapi-validation-core/src/test/java/com/getyourguide/openapi/validation/core/OpenApiRequestValidatorTest.java

@@ -14,30 +14,30 @@
 import java.net.URI;
 import java.util.HashMap;
 import java.util.List;
+import java.util.concurrent.Executor;
 import java.util.concurrent.RejectedExecutionException;
-import java.util.concurrent.ThreadPoolExecutor;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mockito;
 
 public class OpenApiRequestValidatorTest {
 
-    private ThreadPoolExecutor threadPoolExecutor;
+    private Executor executor;
     private OpenApiInteractionValidatorWrapper validator;
 
     private OpenApiRequestValidator openApiRequestValidator;
 
     @BeforeEach
     public void setup() {
-        threadPoolExecutor = mock();
+        executor = mock();
         validator = mock();
         MetricsReporter metricsReporter = mock();
         var mapper = mock(ValidationReportToOpenApiViolationsMapper.class);
         when(mapper.map(any(), any(), any(), any(), any())).thenReturn(List.of());
 
         openApiRequestValidator = new OpenApiRequestValidator(
-            threadPoolExecutor,
+            executor,
             metricsReporter,
             validator,
             mapper,
@@ -47,7 +47,7 @@ public void setup() {
 
     @Test
     public void testWhenThreadPoolExecutorRejectsExecutionThenItShouldNotThrow() {
-        Mockito.doThrow(new RejectedExecutionException()).when(threadPoolExecutor).execute(any());
+        Mockito.doThrow(new RejectedExecutionException()).when(executor).execute(any());
 
         openApiRequestValidator.validateRequestObjectAsync(mock(), null, null, mock());
     }

spring-boot-starter/spring-boot-starter-core/src/main/java/com/getyourguide/openapi/validation/autoconfigure/LibraryAutoConfiguration.java

@@ -25,6 +25,7 @@
 import com.getyourguide.openapi.validation.core.mapper.ValidationReportToOpenApiViolationsMapper;
 import com.getyourguide.openapi.validation.core.metrics.DefaultMetricsReporter;
 import java.util.Optional;
+import java.util.concurrent.Executor;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
@@ -104,14 +105,7 @@ public OpenApiRequestValidator openApiRequestValidator(
         MetricsReporter metricsReporter,
         ValidatorConfiguration validatorConfiguration
     ) {
-        var threadPoolExecutor = new ThreadPoolExecutor(
-            2,
-            2,
-            1000L,
-            TimeUnit.MILLISECONDS,
-            new LinkedBlockingQueue<>(10),
-            new ThreadPoolExecutor.DiscardPolicy()
-        );
+        var threadPoolExecutor = createThreadPoolExecutor();
 
         return new OpenApiRequestValidator(
             threadPoolExecutor,
@@ -122,4 +116,30 @@ public OpenApiRequestValidator openApiRequestValidator(
             properties.toOpenApiRequestValidationConfiguration()
         );
     }
+
+    private Executor createThreadPoolExecutor() {
+        try {
+            // Try to use virtual threads if available (Java 21+)
+            var virtualThreadFactory = Thread.ofVirtual().factory();
+            return new ThreadPoolExecutor(
+                2,
+                2,
+                1000L,
+                TimeUnit.MILLISECONDS,
+                new LinkedBlockingQueue<>(10),
+                virtualThreadFactory,
+                new ThreadPoolExecutor.DiscardPolicy()
+            );
+        } catch (UnsupportedOperationException | NoSuchMethodError e) {
+            // Fallback to ThreadPoolExecutor with regular threads for older Java versions
+            return new ThreadPoolExecutor(
+                2,
+                2,
+                1000L,
+                TimeUnit.MILLISECONDS,
+                new LinkedBlockingQueue<>(10),
+                new ThreadPoolExecutor.DiscardPolicy()
+            );
+        }
+    }
 }

spring-boot-starter/spring-boot-starter-web/src/test/java/com/getyourguide/openapi/validation/integration/controller/DefaultRestController.java

@@ -4,6 +4,7 @@
 import com.getyourguide.openapi.validation.test.exception.WithoutResponseStatusException;
 import com.getyourguide.openapi.validation.test.openapi.web.DefaultApi;
 import com.getyourguide.openapi.validation.test.openapi.web.model.PostTestRequest;
+import com.getyourguide.openapi.validation.test.openapi.web.model.TestEmailResponse;
 import com.getyourguide.openapi.validation.test.openapi.web.model.TestResponse;
 import java.time.LocalDate;
 import java.util.Objects;
@@ -26,6 +27,11 @@ public ResponseEntity<TestResponse> getTest(String testCase, LocalDate date, Str
         return ResponseEntity.ok(new TestResponse().value(responseValue));
     }
 
+    @Override
+    public ResponseEntity<TestEmailResponse> getTestEmail() {
+        return ResponseEntity.ok(new TestEmailResponse().email("[email protected]"));
+    }
+
     @Override
     public ResponseEntity<TestResponse> postTest(PostTestRequest postTestRequest) {
         var responseStatus = postTestRequest.getResponseStatusCode();