diff --git a/src/main/java/org/springframework/samples/petclinic/repository/jdbc/JdbcPetVisitExtractor.java b/src/main/java/org/springframework/samples/petclinic/repository/jdbc/JdbcPetVisitExtractor.java
index 922d608fe143f28374a8461f781812b899883daf..c40786d937e21973c4bb593afa5021b43f89d5ad 100644
--- a/src/main/java/org/springframework/samples/petclinic/repository/jdbc/JdbcPetVisitExtractor.java
+++ b/src/main/java/org/springframework/samples/petclinic/repository/jdbc/JdbcPetVisitExtractor.java
@@ -16,11 +16,16 @@
 package org.springframework.samples.petclinic.repository.jdbc;
 
 import org.springframework.data.jdbc.core.OneToManyResultSetExtractor;
+import org.springframework.jdbc.core.ResultSetExtractor;
 import org.springframework.samples.petclinic.model.Visit;
 
 import java.sql.ResultSet;
 import java.sql.SQLException;
 
+/**
+ * {@link ResultSetExtractor} implementation by using the
+ * {@link OneToManyResultSetExtractor} of Spring Data Core JDBC Extensions.
+ */
 public class JdbcPetVisitExtractor extends
         OneToManyResultSetExtractor<JdbcPet, Visit, Integer> {
 
@@ -37,8 +42,7 @@ public class JdbcPetVisitExtractor extends
     protected Integer mapForeignKey(ResultSet rs) throws SQLException {
         if (rs.getObject("visits.pet_id") == null) {
             return null;
-        }
-        else {
+        } else {
             return rs.getInt("visits.pet_id");
         }
     }
diff --git a/src/main/java/org/springframework/samples/petclinic/repository/jdbc/JdbcVisitRowMapper.java b/src/main/java/org/springframework/samples/petclinic/repository/jdbc/JdbcVisitRowMapper.java
index 241a7902bb3ce3320abd9378a0040b2cb8aaf800..d6dd0cbf8bd3f506c5c7a4b9679f20387e5d5e3a 100644
--- a/src/main/java/org/springframework/samples/petclinic/repository/jdbc/JdbcVisitRowMapper.java
+++ b/src/main/java/org/springframework/samples/petclinic/repository/jdbc/JdbcVisitRowMapper.java
@@ -24,6 +24,10 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.Date;
 
+/**
+ * {@link RowMapper} implementation mapping data from a {@link ResultSet} to the corresponding properties
+ * of the {@link Visit} class.
+ */
 class JdbcVisitRowMapper implements RowMapper<Visit> {
 
     @Override