DATACMNS-1259 - Polishing.

Refactored lambdas to method references. Simplified type parameter. Added comment to test to indicate related issue.

Original pull request: #273.

src/main/java/org/springframework/data/auditing/DefaultAuditableBeanWrapperFactory.java

@@ -113,7 +113,7 @@ class DefaultAuditableBeanWrapperFactory implements AuditableBeanWrapperFactory
 		public TemporalAccessor setCreatedDate(TemporalAccessor value) {
 
 			auditable.setCreatedDate(
-					getAsTemporalAccessor(Optional.of(value), type).orElseThrow(() -> new IllegalStateException()));
+					getAsTemporalAccessor(Optional.of(value), type).orElseThrow(IllegalStateException::new));
 
 			return value;
 		}
@@ -147,7 +147,7 @@ class DefaultAuditableBeanWrapperFactory implements AuditableBeanWrapperFactory
 		public TemporalAccessor setLastModifiedDate(TemporalAccessor value) {
 
 			auditable.setLastModifiedDate(
-					getAsTemporalAccessor(Optional.of(value), type).orElseThrow(() -> new IllegalStateException()));
+					getAsTemporalAccessor(Optional.of(value), type).orElseThrow(IllegalStateException::new));
 
 			return value;
 		}
@@ -220,7 +220,7 @@ class DefaultAuditableBeanWrapperFactory implements AuditableBeanWrapperFactory
 		 * @return
 		 */
 		@SuppressWarnings("unchecked")
-		protected <T extends TemporalAccessor> Optional<T> getAsTemporalAccessor(Optional<? extends Object> source,
+		protected <T extends TemporalAccessor> Optional<T> getAsTemporalAccessor(Optional<?> source,
 				Class<? extends T> target) {
 
 			return source.map(it -> {

src/test/java/org/springframework/data/auditing/MappingAuditableBeanWrapperFactoryUnitTests.java

@@ -163,7 +163,7 @@ public class MappingAuditableBeanWrapperFactoryUnitTests {
 				ThreeTenBackPortConverters.LocalDateTimeToJsr310LocalDateTimeConverter.INSTANCE.convert(reference));
 	}
 
-	@Test
+	@Test // DATACMNS-1109
 	public void exposesInstantAsModificationDate() {
 
 		SampleWithInstant sample = new SampleWithInstant();