DATAMONGO-549 - Fixed potential NullPointerException in MongoTemplate.

Added assertions and guards against MongoPersistentEntity lookups resulting in null values.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java

@@ -733,15 +733,20 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	}
 
 	public void save(Object objectToSave) {
+
+		Assert.notNull(objectToSave);
 		save(objectToSave, determineEntityCollectionName(objectToSave));
 	}
 
 	public void save(Object objectToSave, String collectionName) {
 
+		Assert.notNull(objectToSave);
+		Assert.hasText(collectionName);
+
 		MongoPersistentEntity<?> mongoPersistentEntity = getPersistentEntity(objectToSave.getClass());
 
 		// No optimistic locking -> simple save
-		if (!mongoPersistentEntity.hasVersionProperty()) {
+		if (mongoPersistentEntity == null || !mongoPersistentEntity.hasVersionProperty()) {
 			doSave(collectionName, objectToSave, this.mongoConverter);
 			return;
 		}
@@ -993,7 +998,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	private void assertUpdateableIdIfNotSet(Object entity) {
 
 		MongoPersistentEntity<?> persistentEntity = mappingContext.getPersistentEntity(entity.getClass());
-		MongoPersistentProperty idProperty = persistentEntity.getIdProperty();
+		MongoPersistentProperty idProperty = persistentEntity == null ? null : persistentEntity.getIdProperty();
 
 		if (idProperty == null) {
 			return;

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/MongoTemplateTests.java

@@ -24,8 +24,10 @@ import static org.springframework.data.mongodb.core.query.Update.*;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Date;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 
 import org.bson.types.ObjectId;
 import org.joda.time.DateTime;
@@ -43,6 +45,7 @@ import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.dao.OptimisticLockingFailureException;
 import org.springframework.data.annotation.Id;
 import org.springframework.data.annotation.PersistenceConstructor;
+import org.springframework.data.mapping.model.MappingException;
 import org.springframework.data.mongodb.InvalidMongoDbApiUsageException;
 import org.springframework.data.mongodb.MongoDbFactory;
 import org.springframework.data.mongodb.core.convert.CustomConversions;
@@ -1322,6 +1325,33 @@ public class MongoTemplateTests {
 		assertThat(template.findAll(PersonWithConvertedId.class, collectionName).isEmpty(), is(true));
 	}
 
+	/**
+	 * @see DATAMONGO-549
+	 */
+	public void savesMapCorrectly() {
+
+		Map<String, String> map = new HashMap<String, String>();
+		map.put("key", "value");
+
+		template.save(map, "maps");
+	}
+
+	/**
+	 * @see DATAMONGO-549
+	 */
+	@Test(expected = MappingException.class)
+	public void savesMongoPrimitiveObjectCorrectly() {
+		template.save(new Object(), "collection");
+	}
+
+	/**
+	 * @see DATAMONGO-549
+	 */
+	@Test(expected = IllegalArgumentException.class)
+	public void rejectsNullObjectToBeSaved() {
+		template.save(null);
+	}
+
 	static class MyId {
 
 		String first;