[4.x] Register a low-priority exception mapper to log internal errors

reactive/webserver/jersey/src/main/java/io/helidon/reactive/webserver/jersey/JerseySupport.java

@@ -50,11 +50,16 @@
 import io.helidon.reactive.webserver.jersey.HelidonHK2InjectionManagerFactory.InjectionManagerWrapper;
 import io.helidon.tracing.SpanContext;
 
+import jakarta.annotation.Priority;
+import jakarta.ws.rs.InternalServerErrorException;
+import jakarta.ws.rs.Priorities;
 import jakarta.ws.rs.core.Application;
 import jakarta.ws.rs.core.Configurable;
 import jakarta.ws.rs.core.Configuration;
 import jakarta.ws.rs.core.GenericType;
+import jakarta.ws.rs.core.Response;
 import jakarta.ws.rs.core.SecurityContext;
+import jakarta.ws.rs.ext.ExceptionMapper;
 import org.glassfish.jersey.CommonProperties;
 import org.glassfish.jersey.internal.MapPropertiesDelegate;
 import org.glassfish.jersey.internal.inject.InjectionManager;
@@ -137,6 +142,9 @@ private JerseySupport(Builder builder) {
         serviceShutdownHook = new Thread(service::shutdownNow);
         Runtime.getRuntime().addShutdownHook(serviceShutdownHook);
 
+        // Register an error mapper to log internal exceptions in Jersey
+        builder.resourceConfig.register(InternalErrorMapper.class);
+
         // make sure we have a wrapped async executor as well
         if (builder.asyncExecutorService == null) {
             // create a new one from configuration
@@ -503,6 +511,15 @@ private Builder(Application application) {
             }
         }
 
+        /**
+         * This method is used for testing only.
+         *
+         * @return underlying resource config.
+         */
+        ResourceConfig resourceConfig() {
+            return resourceConfig;
+        }
+
         /**
          * Jersey Module builder class for convenient creating {@link JerseySupport}.
          *
@@ -662,4 +679,19 @@ public void reload(ResourceConfig configuration) {
             throw new UnsupportedOperationException("Reloading is not supported in Helidon");
         }
     }
+
+    /**
+     * A low priority mapper to catch internal exceptions in Jersey and log them.
+     * Otherwise, these errors can get lost and never reported by Helidon. One example
+     * is a {@code ClassNotFoundException} exception in Jersey's code.
+     */
+    @Priority(Priorities.USER + 1000)
+    static class InternalErrorMapper implements ExceptionMapper<InternalServerErrorException> {
+
+        @Override
+        public Response toResponse(InternalServerErrorException e) {
+            LOGGER.log(Level.FINE, "Internal error thrown by Jersey", e);
+            return Response.status(500).build();
+        }
+    }
 }

reactive/webserver/jersey/src/main/java/module-info.java

@@ -40,5 +40,5 @@
     provides InjectionManagerFactory with HelidonHK2InjectionManagerFactory;
 
     // reflection access from jersey injection
-    opens io.helidon.reactive.webserver.jersey to org.glassfish.hk2.utilities, org.glassfish.hk2.locator;
+    opens io.helidon.reactive.webserver.jersey to org.glassfish.hk2.utilities, org.glassfish.hk2.locator, weld.core.impl;
 }

reactive/webserver/jersey/src/test/java/io/helidon/reactive/webserver/jersey/JerseySupportTest.java

@@ -40,7 +40,9 @@
 import static io.helidon.reactive.webserver.jersey.JerseySupport.basePath;
 import static org.hamcrest.CoreMatchers.endsWith;
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 /**
@@ -338,6 +340,14 @@ public void testJerseyProperties() {
         assertThat(System.getProperty(IGNORE_EXCEPTION_RESPONSE), is("true"));
     }
 
+    @Test
+    public void testInternalErrorMapper() {
+        JerseySupport.Builder builder = JerseySupport.builder();
+        JerseySupport jerseySupport = builder.build();
+        assertThat(jerseySupport, is(notNullValue()));
+        assertThat(builder.resourceConfig().getClasses(), contains(JerseySupport.InternalErrorMapper.class));
+    }
+
     static class PathMockup implements ServerRequest.Path {
         private final String absolutePath;
         private final String path;