DATACMNS-479 - Make sure Map types are not added to the mapping context.

Changed the algorithm for nested PersistentEntity detection to only use PersistentProperty.getPersistentEntityTypes(…) and make sure we return unwrap Maps and Collections inside the method correctly.

src/test/java/org/springframework/data/mapping/context/AbstractMappingContextUnitTests.java

@@ -23,6 +23,7 @@ import groovy.lang.MetaClass;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import java.util.TreeMap;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -231,7 +232,33 @@ public class AbstractMappingContextUnitTests {
 	public void hasPersistentEntityForCollectionPropertiesAfterInitialization() {
 
 		context.getPersistentEntity(Sample.class);
-		assertThat(context.hasPersistentEntityFor(Person.class), is(true));
+		assertHasEntityFor(Person.class, context, true);
+	}
+
+	/**
+	 * @see DATACMNS-479
+	 */
+	@Test
+	public void doesNotAddMapImplementationClassesAsPersistentEntity() {
+
+		context.getPersistentEntity(Sample.class);
+		assertHasEntityFor(TreeMap.class, context, false);
+	}
+
+	private static void assertHasEntityFor(Class<?> type, SampleMappingContext context, boolean expected) {
+
+		boolean found = false;
+
+		for (BasicPersistentEntity<Object, SamplePersistentProperty> entity : context.getPersistentEntities()) {
+			if (entity.getType().equals(type)) {
+				found = true;
+				break;
+			}
+		}
+
+		if (found != expected) {
+			fail(String.format("%s to find persistent entity for %s!", expected ? "Expected" : "Did not expect", type));
+		}
 	}
 
 	class Person {
@@ -246,6 +273,7 @@ public class AbstractMappingContextUnitTests {
 
 		MetaClass metaClass;
 		List<Person> persons;
+		TreeMap<String, Person> personMap;
 	}
 
 	static class Base {