Avoid potential NPE when collecting RESTEasy Providers on Resource classes

extensions/resteasy-classic/resteasy-common/deployment/src/main/java/io/quarkus/resteasy/common/deployment/ResteasyCommonProcessor.java

@@ -531,8 +531,10 @@ private static boolean collectDeclaredProvidersForMethodAndMediaTypeAnnotation(S
             AnnotationInstance mediaTypeClassAnnotationInstance = methodTarget.declaringClass()
                     .classAnnotation(mediaTypeAnnotation);
             if (mediaTypeClassAnnotationInstance != null) {
-                if (collectDeclaredProvidersForMediaTypeAnnotationInstance(providersToRegister, categorizedProviders,
-                        mediaTypeClassAnnotationInstance.value().asStringArray(), methodTarget)) {
+                AnnotationValue mediaTypeClassValue = mediaTypeClassAnnotationInstance.value();
+                if ((mediaTypeClassValue != null)
+                        && collectDeclaredProvidersForMediaTypeAnnotationInstance(providersToRegister, categorizedProviders,
+                                mediaTypeClassValue.asStringArray(), methodTarget)) {
                     return true;
                 }
                 return false;

extensions/resteasy-classic/resteasy/deployment/src/test/java/io/quarkus/resteasy/test/NoProducesValueTest.java

@@ -0,0 +1,38 @@
+package io.quarkus.resteasy.test;
+
+import static io.restassured.RestAssured.given;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+import javax.ws.rs.core.Response;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.test.QuarkusUnitTest;
+
+public class NoProducesValueTest {
+
+    @RegisterExtension
+    static QuarkusUnitTest runner = new QuarkusUnitTest()
+            .withApplicationRoot((jar) -> jar
+                    .addClasses(TestResource.class));
+
+    @Test
+    public void testSomething() {
+        given().when().get("/test/hello")
+                .then().statusCode(200);
+    }
+
+    @Produces
+    @Path("test")
+    public static class TestResource {
+
+        @GET
+        @Path("hello")
+        public Response getHello() {
+            return Response.ok().build();
+        }
+    }
+}