Customizing Java 8 code in modemmapper package

java-collections-conversions-2/src/main/java/com/baeldung/modelmapper/MapperUtil.java

@@ -2,11 +2,11 @@ package com.baeldung.modelmapper;
 
 import org.modelmapper.ModelMapper;
 
-import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
- * This is a helper class that contains methods for generic mapping of the users list.
+ * This is a helper class that contains method for generic mapping of the users list.
  * Initially, an instance of ModelMapper was created.
  *
  * @author Sasa Milenkovic
@@ -21,14 +21,12 @@ public class MapperUtil {
 
     }
 
-    public static <S, T> List<T> mapList(List<S> sourceList, Class<T> target) {
-        List<T> targetList = new ArrayList<T>();
+    public static <S, T> List<T> mapList(List<S> source, Class<T> targetClass) {
 
-        for (S source : sourceList) {
-            targetList.add(modelMapper.map(source, target));
-        }
-
-        return targetList;
+        return source
+                .stream()
+                .map(element -> modelMapper.map(element, targetClass))
+                .collect(Collectors.toList());
     }
 
 }

java-collections-conversions-2/src/main/java/com/baeldung/modelmapper/UserPropertyMap.java

@@ -4,11 +4,11 @@ import org.modelmapper.AbstractConverter;
 import org.modelmapper.Converter;
 import org.modelmapper.PropertyMap;
 
-import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
- * UserPropertyMap class instantiates the converter to map the data from the user list to the user name list.
+ * UserPropertyMap class instantiates the converter to map the data from the UserList to the UsersLisDTO.
  * In the configuration method, we call a converter to do the mapping.
  *
  * @author Sasa Milenkovic
@@ -18,19 +18,20 @@ public class UserPropertyMap extends PropertyMap<UserList, UserListDTO> {
 
     Converter<List<User>, List<String>> converter = new AbstractConverter<List<User>, List<String>>() {
 
-        protected List<String> usernames;
 
         @Override
         protected List<String> convert(List<User> users) {
 
-            usernames = new ArrayList<String>();
-            users.forEach(user -> usernames.add(user.getUsername()));
-            return usernames;
+            return users
+                    .stream()
+                    .map(User::getUsername)
+                    .collect(Collectors.toList());
         }
     };
 
     @Override
     protected void configure() {
+
         using(converter).map(source.getUsers(), destination.getUsernames());
     }
 }