HHH-19918 Avoid reflection when instantiating known FormatMapper

Author: beikov

hibernate-core/src/main/java/org/hibernate/type/format/jackson/JacksonIntegration.java

@@ -4,7 +4,12 @@
  */
 package org.hibernate.type.format.jackson;
 
+import java.util.List;
+
+import com.fasterxml.jackson.databind.Module;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import org.checkerframework.checker.nullness.qual.Nullable;
+
 import org.hibernate.type.format.FormatMapper;
 import org.hibernate.type.format.FormatMapperCreationContext;
 
@@ -36,72 +41,37 @@ private static boolean ableToLoadJacksonXMLMapper() {
 	 */
 	private static boolean ableToLoadJacksonOSONFactory() {
 		return ableToLoadJacksonJSONMapper() &&
-				canLoad( "oracle.jdbc.provider.oson.OsonFactory" );
+			   canLoad( "oracle.jdbc.provider.oson.OsonFactory" );
 	}
 
 	public static @Nullable FormatMapper getXMLJacksonFormatMapperOrNull(FormatMapperCreationContext creationContext) {
 		return JACKSON_XML_AVAILABLE
-				? createFormatMapper( "org.hibernate.type.format.jackson.JacksonXmlFormatMapper", creationContext )
+				? new JacksonXmlFormatMapper( creationContext )
 				: null;
 	}
 
 	public static @Nullable FormatMapper getJsonJacksonFormatMapperOrNull(FormatMapperCreationContext creationContext) {
 		return JACKSON_JSON_AVAILABLE
-				? createFormatMapper( "org.hibernate.type.format.jackson.JacksonJsonFormatMapper", creationContext )
+				? new JacksonJsonFormatMapper( creationContext )
 				: null;
 	}
 	public static @Nullable FormatMapper getOsonJacksonFormatMapperOrNull(FormatMapperCreationContext creationContext) {
 		return JACKSON_OSON_AVAILABLE
-				? createFormatMapper( "org.hibernate.type.format.jackson.JacksonOsonFormatMapper", creationContext )
+				? new JacksonOsonFormatMapper( creationContext )
 				: null;
 	}
 
-	public static @Nullable FormatMapper getXMLJacksonFormatMapperOrNull(boolean legacyFormat) {
-		if ( JACKSON_XML_AVAILABLE ) {
-			try {
-				final Class<?> formatMapperClass = JacksonIntegration.class.getClassLoader()
-						.loadClass( "org.hibernate.type.format.jackson.JacksonXmlFormatMapper" );
-				return (FormatMapper) formatMapperClass.getDeclaredConstructor( boolean.class )
-						.newInstance( legacyFormat );
-			}
-			catch (Exception e) {
-				throw new RuntimeException( "Couldn't instantiate Jackson XML FormatMapper", e );
-			}
-		}
-		return null;
-	}
-
 	public static @Nullable FormatMapper getJsonJacksonFormatMapperOrNull() {
 		return JACKSON_JSON_AVAILABLE
-				? createFormatMapper( "org.hibernate.type.format.jackson.JacksonJsonFormatMapper", null )
+				? new JacksonJsonFormatMapper()
 				: null;
 	}
 	public static @Nullable FormatMapper getOsonJacksonFormatMapperOrNull() {
 		return JACKSON_OSON_AVAILABLE
-				? createFormatMapper( "org.hibernate.type.format.jackson.JacksonOsonFormatMapper", null )
+				? new JacksonOsonFormatMapper()
 				: null;
 	}
 
-	private static FormatMapper createFormatMapper(String className, @Nullable FormatMapperCreationContext creationContext) {
-		try {
-			if ( creationContext == null ) {
-				final Class<?> formatMapperClass = JacksonIntegration.class.getClassLoader()
-						.loadClass( className );
-				return (FormatMapper) formatMapperClass.getDeclaredConstructor().newInstance();
-			}
-			else {
-				return (FormatMapper) creationContext.getBootstrapContext()
-						.getClassLoaderAccess()
-						.classForName( className )
-						.getDeclaredConstructor( FormatMapperCreationContext.class )
-						.newInstance( creationContext );
-			}
-		}
-		catch (Exception e) {
-			throw new RuntimeException( "Couldn't instantiate Jackson FormatMapper", e );
-		}
-	}
-
 	/**
 	 * Checks that Oracle OSON extension available
 	 *
@@ -124,4 +94,27 @@ private static boolean canLoad(String name) {
 			return false;
 		}
 	}
+
+	static List<Module> loadModules(FormatMapperCreationContext creationContext) {
+		final ClassLoader classLoader = JacksonIntegration.class.getClassLoader();
+		final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
+		if ( contextClassLoader != null && classLoader != contextClassLoader ) {
+			try {
+				// The context class loader represents the application class loader in a Jakarta EE deployment.
+				// We have to check if the ObjectMapper that is visible to Hibernate ORM is the same that is visible
+				// to the application class loader. Only if it is, we can use the application class loader or rather
+				// our AggregatedClassLoader for loading Jackson Module via ServiceLoader, as otherwise the loaded
+				// Jackson Module instances would have a different class loader, leading to a ClassCastException.
+				if ( ObjectMapper.class == contextClassLoader.loadClass( "com.fasterxml.jackson.databind.ObjectMapper" ) ) {
+					return creationContext.getBootstrapContext()
+							.getClassLoaderService()
+							.<List<Module>>workWithClassLoader( ObjectMapper::findModules );
+				}
+			}
+			catch (ClassNotFoundException | LinkageError e) {
+				// Ignore if the context/application class loader doesn't know Jackson classes
+			}
+		}
+		return ObjectMapper.findModules( classLoader );
+	}
 }

hibernate-core/src/main/java/org/hibernate/type/format/jackson/JacksonJsonFormatMapper.java

@@ -34,11 +34,7 @@ public JacksonJsonFormatMapper() {
 	}
 
 	public JacksonJsonFormatMapper(FormatMapperCreationContext creationContext) {
-		this(
-				creationContext.getBootstrapContext()
-						.getClassLoaderService()
-						.<List<Module>>workWithClassLoader( ObjectMapper::findModules )
-		);
+		this( JacksonIntegration.loadModules( creationContext ) );
 	}
 
 	private JacksonJsonFormatMapper(List<Module> modules) {

hibernate-core/src/main/java/org/hibernate/type/format/jackson/JacksonXmlFormatMapper.java

@@ -57,17 +57,15 @@ public JacksonXmlFormatMapper() {
 
 	public JacksonXmlFormatMapper(boolean legacyFormat) {
 		this(
-				createXmlMapper( XmlMapper.findModules( JacksonXmlFormatMapper.class.getClassLoader() ), legacyFormat ),
+				createXmlMapper( ObjectMapper.findModules( JacksonXmlFormatMapper.class.getClassLoader() ), legacyFormat ),
 				legacyFormat
 		);
 	}
 
 	public JacksonXmlFormatMapper(FormatMapperCreationContext creationContext) {
 		this(
 				createXmlMapper(
-						creationContext.getBootstrapContext()
-								.getClassLoaderService()
-								.<List<Module>>workWithClassLoader( XmlMapper::findModules ),
+						JacksonIntegration.loadModules( creationContext ),
 						creationContext.getBootstrapContext()
 								.getMetadataBuildingOptions()
 								.isXmlFormatMapperLegacyFormatEnabled()