DATAMONGO-1605 - Polishing.

Remove additional quoting around JSON serialization because JSON serialization adds quotes to a string. Reformat code.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/ExpressionEvaluatingParameterBinder.java

@@ -219,10 +219,6 @@ class ExpressionEvaluatingParameterBinder {
 			return base64representation;
 		}
 
-		if (binding.isExpression() && value instanceof String) {
-			return "\"" + JSON.serialize(value) + "\"";
-		}
-
 		return JSON.serialize(value);
 	}
 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/repository/query/StringBasedMongoQueryUnitTests.java

@@ -519,7 +519,7 @@ public class StringBasedMongoQueryUnitTests {
 	public void findUsingSpelShouldRetainNullValues() throws Exception {
 
 		StringBasedMongoQuery mongoQuery = createQueryForMethod("findByUsingSpel", Object.class);
-		ConvertingParameterAccessor accessor = StubParameterAccessor.getAccessor(converter, new Object[]{null});
+		ConvertingParameterAccessor accessor = StubParameterAccessor.getAccessor(converter, new Object[] { null });
 
 		org.springframework.data.mongodb.core.query.Query query = mongoQuery.createQuery(accessor);
 		assertThat(query.getQueryObject(), is(new Document("arg0", null)));