#284 - Do not create PersistentEntity for UUID.

We now no longer create a PersistentEntity for UUID as UUID is a simple type and introspection on Java 9+ causes illegal access warnings.

src/main/java/org/springframework/data/r2dbc/mapping/R2dbcMappingContext.java

@@ -15,8 +15,10 @@
  */
 package org.springframework.data.r2dbc.mapping;
 
+import org.springframework.core.KotlinDetector;
 import org.springframework.data.relational.core.mapping.NamingStrategy;
 import org.springframework.data.relational.core.mapping.RelationalMappingContext;
+import org.springframework.data.util.KotlinReflectionUtils;
 import org.springframework.data.util.TypeInformation;
 
 /**
@@ -46,6 +48,11 @@ public class R2dbcMappingContext extends RelationalMappingContext {
 	 */
 	@Override
 	protected boolean shouldCreatePersistentEntityFor(TypeInformation<?> type) {
-		return !R2dbcSimpleTypeHolder.HOLDER.isSimpleType(type.getType());
+
+		if (R2dbcSimpleTypeHolder.HOLDER.isSimpleType(type.getType())) {
+			return false;
+		}
+
+		return !KotlinDetector.isKotlinType(type.getType()) || KotlinReflectionUtils.isSupportedKotlinClass(type.getType());
 	}
 }

src/main/java/org/springframework/data/r2dbc/mapping/R2dbcSimpleTypeHolder.java

@@ -23,6 +23,7 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
+import java.util.UUID;
 
 import org.springframework.data.mapping.model.SimpleTypeHolder;
 
@@ -36,8 +37,8 @@ public class R2dbcSimpleTypeHolder extends SimpleTypeHolder {
 	/**
 	 * Set of R2DBC simple types.
 	 */
-	public static final Set<Class<?>> R2DBC_SIMPLE_TYPES = Collections
+	public static final Set<Class<?>> R2DBC_SIMPLE_TYPES = Collections.unmodifiableSet(
-			.unmodifiableSet(new HashSet<>(Arrays.asList(OutboundRow.class, Row.class, BigInteger.class, BigDecimal.class)));
+			new HashSet<>(Arrays.asList(OutboundRow.class, Row.class, BigInteger.class, BigDecimal.class, UUID.class)));
 
 	public static final SimpleTypeHolder HOLDER = new R2dbcSimpleTypeHolder();
 

src/test/java/org/springframework/data/r2dbc/mapping/R2dbcMappingContextUnitTests.java

@@ -19,14 +19,21 @@ import static org.assertj.core.api.Assertions.*;
 
 import io.r2dbc.spi.Row;
 
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.UUID;
 
 import org.junit.Test;
 
 import org.springframework.core.convert.converter.Converter;
+import org.springframework.data.convert.CustomConversions;
 import org.springframework.data.convert.ReadingConverter;
 import org.springframework.data.convert.WritingConverter;
 import org.springframework.data.r2dbc.convert.R2dbcCustomConversions;
+import org.springframework.data.r2dbc.dialect.PostgresDialect;
+import org.springframework.data.r2dbc.dialect.R2dbcDialect;
 
 /**
  * Unit tests for {@link R2dbcMappingContext}.
@@ -47,6 +54,27 @@ public class R2dbcMappingContextUnitTests {
 		assertThat(context.getPersistentEntity(ConvertedEntity.class)).isNotNull();
 	}
 
+	@Test // gh-284
+	public void shouldNotCreateEntityForUUID() {
+
+		R2dbcDialect dialect = PostgresDialect.INSTANCE;
+
+		List<Object> converters = new ArrayList<>(dialect.getConverters());
+		converters.addAll(R2dbcCustomConversions.STORE_CONVERTERS);
+
+		CustomConversions.StoreConversions storeConversions = CustomConversions.StoreConversions
+				.of(dialect.getSimpleTypeHolder(), converters);
+
+		R2dbcCustomConversions conversions = new R2dbcCustomConversions(storeConversions, Collections.emptyList());
+
+		R2dbcMappingContext context = new R2dbcMappingContext();
+		context.setSimpleTypeHolder(conversions.getSimpleTypeHolder());
+		context.afterPropertiesSet();
+
+		assertThat(context.getPersistentEntity(MyEntity.class)).isNotNull();
+		assertThat(context.getPersistentEntity(UUID.class)).isNull();
+	}
+
 	static class ConvertedEntity {
 
 	}
@@ -73,4 +101,9 @@ public class R2dbcMappingContextUnitTests {
 			return new ConvertedEntity();
 		}
 	}
+
+	static class MyEntity {
+
+		UUID id;
+	}
 }