diff --git a/src/Common/src/main/java/greenify/common/ApplicationException.java b/src/Common/src/main/java/greenify/common/ApplicationException.java
index f64b9fd..d748ea6 100644
--- a/src/Common/src/main/java/greenify/common/ApplicationException.java
+++ b/src/Common/src/main/java/greenify/common/ApplicationException.java
@@ -2,7 +2,7 @@ package greenify.common;
 
 public class ApplicationException extends RuntimeException {
     /**
-     * This method returns an application exception message.
+     * This method sends an application exception message.
      * @param message the exception message
      */
     public ApplicationException(String message) {
diff --git a/src/Common/src/main/java/greenify/common/ErrorResponse.java b/src/Common/src/main/java/greenify/common/ErrorResponse.java
index df449c6..72ab1b9 100644
--- a/src/Common/src/main/java/greenify/common/ErrorResponse.java
+++ b/src/Common/src/main/java/greenify/common/ErrorResponse.java
@@ -17,7 +17,7 @@ public class ErrorResponse {
     public ErrorResponse() { }
 
     /**
-     * This method returns the message.
+     * This method gets the message.
      * @return the message
      */
     public String getMessage() {
diff --git a/src/Common/src/main/java/greenify/common/UserDto.java b/src/Common/src/main/java/greenify/common/UserDto.java
index 2b83014..d2b9d4f 100644
--- a/src/Common/src/main/java/greenify/common/UserDto.java
+++ b/src/Common/src/main/java/greenify/common/UserDto.java
@@ -6,6 +6,7 @@
   resorting to remote interfaces (e.g., web services),
   where each call is an expensive operation.
  */
+
 package greenify.common;
 
 public class UserDto {
diff --git a/src/Common/src/test/java/ErrorResponseTest.java b/src/Common/src/test/java/ErrorResponseTest.java
index 05892e1..9cce02b 100644
--- a/src/Common/src/test/java/ErrorResponseTest.java
+++ b/src/Common/src/test/java/ErrorResponseTest.java
@@ -1,4 +1,5 @@
 import static org.junit.Assert.assertEquals;
+
 import greenify.common.ErrorResponse;
 import org.junit.Test;
 
diff --git a/src/Common/src/test/java/UserDtoTest.java b/src/Common/src/test/java/UserDtoTest.java
index 565ca0f..90514ae 100644
--- a/src/Common/src/test/java/UserDtoTest.java
+++ b/src/Common/src/test/java/UserDtoTest.java
@@ -1,4 +1,5 @@
 import static org.junit.Assert.assertEquals;
+
 import greenify.common.UserDto;
 import org.junit.Test;
 
diff --git a/src/Server/src/main/java/greenify/server/InputValidator.java b/src/Server/src/main/java/greenify/server/InputValidator.java
index a17b575..9b3f0dc 100644
--- a/src/Server/src/main/java/greenify/server/InputValidator.java
+++ b/src/Server/src/main/java/greenify/server/InputValidator.java
@@ -4,68 +4,69 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 public class InputValidator {
 
     private static final List<InputItem> inputItems = Arrays.asList(
         new InputItem("input_size", false, "1"),
         new InputItem("input_income", false, "40000"),
-        new InputItem("transportation_num_vehicles", false, "1" ),
+        new InputItem("transportation_num_vehicles", false, "1"),
         new InputItem("transportation_miles1", false, "16100", false),
-        new InputItem("transportation_fuels1", false, "2" , false),
-        new InputItem("transportation_mpg1", false, null, false ),
-        new InputItem("transportation_miles2", false, "13200", false ),
-        new InputItem("transportation_fuels2", false, "0" , false),
-        new InputItem("transportation_mpg2", false, "22" ,false),
-        new InputItem("transportation_publicTrans", false, "436" ),
-        new InputItem("transportation_air", false, "3900" ),
-        new InputItem("housing_electricity_kwh_year", false, "12632" ),
-        new InputItem("housing_cleanPercent", false, "0" ),
-        new InputItem("housing_naturalGas_therms_year", false, "472" ),
-        new InputItem("housing_heatingOil_gallons_year", false, "73" ),
-        new InputItem("housing_square_feet", false, "1850" ),
-        new InputItem("housing_water_sewage", false, "100" ),
-        new InputItem("food_meat_fish_eggs", true, "2.4" ),
-        new InputItem("food_grains", true, "4.1" ),
-        new InputItem("food_dairy", true, "2.2" ),
-        new InputItem("food_fruit_vegetables", true, "3.5" ),
-        new InputItem("food_snacks_drinks", true, "3.4" ),
-        new InputItem("shopping_goods", false, "1310" ),
-        new InputItem("shopping_services", false, "2413" )
+        new InputItem("transportation_fuels1", false, "2", false),
+        new InputItem("transportation_mpg1", false, null, false),
+        new InputItem("transportation_miles2", false, "13200", false),
+        new InputItem("transportation_fuels2", false, "0", false),
+        new InputItem("transportation_mpg2", false, "22", false),
+        new InputItem("transportation_publicTrans", false, "436"),
+        new InputItem("transportation_air", false, "3900"),
+        new InputItem("housing_electricity_kwh_year", false, "12632"),
+        new InputItem("housing_cleanPercent", false, "0"),
+        new InputItem("housing_naturalGas_therms_year", false, "472"),
+        new InputItem("housing_heatingOil_gallons_year", false, "73"),
+        new InputItem("housing_square_feet", false, "1850"),
+        new InputItem("housing_water_sewage", false, "100"),
+        new InputItem("food_meat_fish_eggs", true, "2.4"),
+        new InputItem("food_grains", true, "4.1"),
+        new InputItem("food_dairy", true, "2.2"),
+        new InputItem("food_fruit_vegetables", true, "3.5"),
+        new InputItem("food_snacks_drinks", true, "3.4"),
+        new InputItem("shopping_goods", false, "1310"),
+        new InputItem("shopping_services", false, "2413")
     );
 
     /**
-     * The method checks that the id is valid or not.
+     * The method checks whether the id is valid or not.
      * @param inputName the name of input
      * @return true or false
      */
     public static Boolean isValidItem(String inputName) {
-        return inputItems.stream().filter(i -> i.getName() == inputName).findAny().isPresent();
+        return inputItems.stream().anyMatch(i -> i.getName().equals(inputName));
     }
 
     /**
-     * The method checks that the item value is valid or not.
+     * The method checks whether the item value is valid or not.
      * @param inputName the name of input
      * @param value the value of item
      * @return true or false
      */
     public static boolean isValidItemValue(String inputName, String value) {
         InputItem item = null;
-        for (int i = 0; i < inputItems.size(); i++) {
-            if (inputItems.get(i).getName() == inputName) {
-                item = inputItems.get(i);
+        for (InputItem inputItem : inputItems) {
+            if (inputItem.getName().equals(inputName)) {
+                item = inputItem;
             }
         }
-        if (item.getFloat()) {
+        if (Objects.requireNonNull(item).getFloat()) {
             try {
-                Float number = Float.parseFloat(value);
+                Float.parseFloat(value);
             } catch (NumberFormatException | NullPointerException nfe) {
                 return false;
             }
             return true;
         } else {
             try {
-                Integer number = Integer.parseInt(value);
+                Integer.parseInt(value);
             } catch (NumberFormatException | NullPointerException nfe) {
                 return false;
             }
@@ -74,13 +75,13 @@ public class InputValidator {
     }
 
     /**
-     * getter for default values.
+     * This method gets default values.
      * @return the map of default values
      */
     public static Map<String, String> getDefaultValues() {
-        Map<String,String> map = new HashMap<String, String>(){};
-        for (int i = 0; i < inputItems.size(); i++) {
-            map.put(inputItems.get(i).getName(), inputItems.get(i).getDefaultValue());
+        Map<String, String> map = new HashMap<String, String>() { };
+        for (InputItem inputItem : inputItems) {
+            map.put(inputItem.getName(), inputItem.getDefaultValue());
         }
         return map;
     }
diff --git a/src/Server/src/main/java/greenify/server/data/model/User.java b/src/Server/src/main/java/greenify/server/data/model/User.java
index 595947b..d126aeb 100644
--- a/src/Server/src/main/java/greenify/server/data/model/User.java
+++ b/src/Server/src/main/java/greenify/server/data/model/User.java
@@ -57,7 +57,7 @@ public class User {
     }
 
     /**
-     * This method returns the ID of the user.
+     * This method gets the ID of the user.
      * @return the id of the user
      */
     public Long getId() {
@@ -73,7 +73,7 @@ public class User {
     }
 
     /**
-     * This method returns the name of the user.
+     * This method gets the name of the user.
      * @return the name of the user
      */
     public String getName() {
@@ -89,7 +89,7 @@ public class User {
     }
 
     /**
-     * This method returns the password of the user.
+     * This method gets the password of the user.
      * @return the password of the user
      */
     public String getPassword() {
@@ -105,7 +105,7 @@ public class User {
     }
 
     /**
-     * This method returns the footPrint of user.
+     * This method gets the footPrint of user.
      * @return the footprint of the user
      */
     public Float getFootPrint() {
@@ -121,7 +121,7 @@ public class User {
     }
 
     /**
-     * This method returns the footprint inputs of the user.
+     * This method gets the footprint inputs of the user.
      * @return footprint inputs of the user
      */
     public Map<String, String> getFootPrintInputs() {
@@ -155,7 +155,7 @@ public class User {
     }
 
     /**
-     * This method returns a human readable (JSON) object.
+     * This method gets a human readable (JSON) object.
      * @return the JSON form of the object.
      */
     @Override
@@ -195,7 +195,7 @@ public class User {
     }
 
     /**
-     * This method returns the hashcode of a user.
+     * This method gets the hashcode of a user.
      * @return hashcode of a user
      */
     @Override
diff --git a/src/Server/src/main/java/greenify/server/rest/RestExceptionHandler.java b/src/Server/src/main/java/greenify/server/rest/RestExceptionHandler.java
index d4657cc..ff5d444 100644
--- a/src/Server/src/main/java/greenify/server/rest/RestExceptionHandler.java
+++ b/src/Server/src/main/java/greenify/server/rest/RestExceptionHandler.java
@@ -7,12 +7,14 @@ import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
 
-//class that handles exceptions for the rest server
+/**
+ * This class handles exceptions for the REST server.
+ */
 @RestControllerAdvice
-public class RestExceptionHandler {
+class RestExceptionHandler {
     @ExceptionHandler(ApplicationException.class)
     @ResponseStatus(HttpStatus.BAD_REQUEST)
-    public static ErrorResponse applicationException(ApplicationException ex) {
+    static ErrorResponse applicationException(ApplicationException ex) {
         return new ErrorResponse(ex.getMessage());
     }
 }
diff --git a/src/Server/src/main/java/greenify/server/rest/UserController.java b/src/Server/src/main/java/greenify/server/rest/UserController.java
index 05ed9db..2d7d3c7 100644
--- a/src/Server/src/main/java/greenify/server/rest/UserController.java
+++ b/src/Server/src/main/java/greenify/server/rest/UserController.java
@@ -11,7 +11,7 @@ import org.springframework.web.bind.annotation.RestController;
 public class UserController {
     @Autowired
     private
-    UserService userService;
+        UserService userService;
 
     /**
      * This method registers the user.
diff --git a/src/Server/src/main/java/greenify/server/service/CalculatorService.java b/src/Server/src/main/java/greenify/server/service/CalculatorService.java
index 7ad64b4..dbf9a65 100644
--- a/src/Server/src/main/java/greenify/server/service/CalculatorService.java
+++ b/src/Server/src/main/java/greenify/server/service/CalculatorService.java
@@ -16,21 +16,27 @@ import org.springframework.web.client.RestTemplate;
 import org.springframework.web.util.UriComponentsBuilder;
 
 import java.util.Map;
+import java.util.Objects;
 
 @Service
-public class CalculatorService {
-    Logger logger = LoggerFactory.getLogger(UserService.class);
-
+class CalculatorService {
     @Autowired
     RestTemplate restTemplate;
 
+    private Logger logger = LoggerFactory.getLogger(UserService.class);
+
     @Bean
     RestTemplate restTemplate(RestTemplateBuilder builder) {
         return builder.build();
     }
 
-    protected Float invokeExternalService(Map<String, String> map) {
-        /**
+    /**
+     * This method invokes the external service that calculates a footprint.
+     * @param map used variables to calculate a footprint
+     * @return a footprint
+     */
+    Float invokeExternalService(Map<String, String> map) {
+        /*
          * curl -X GET "https://apis.berkeley.edu/coolclimate/footprint-sandbox?input_location_mode=1
          * &input_location=48001&input_income=1&input_size=0&input_footprint_transportation_miles1=3
          * &input_footprint_transportation_mpg1=5&input_footprint_transportation_fuel1=0"
@@ -52,7 +58,7 @@ public class CalculatorService {
                 entity, String.class);
         logger.info(response.getStatusCode().toString());
         logger.info(response.getBody());
-        String result = response.getBody().substring(response.getBody()
+        String result = response.getBody().substring(Objects.requireNonNull(response.getBody())
                 .indexOf("<result_grand_total>")
                 + 20, response.getBody().indexOf("</result_grand_total>"));
         // to do: in not HTTP 200 or exception case throws exception
@@ -60,7 +66,12 @@ public class CalculatorService {
         return Float.parseFloat(result);
     }
 
-    public Float calculateFootprint(User user) {
+    /**
+     * The method calculates a users footprint.
+     * @param user the user
+     * @return the footprint of the user
+     */
+    Float calculateFootprint(User user) {
         return invokeExternalService(user.getFootPrintInputs());
     }
 }
diff --git a/src/Server/src/main/java/greenify/server/service/UserService.java b/src/Server/src/main/java/greenify/server/service/UserService.java
index 0f1ec9a..901a0ea 100644
--- a/src/Server/src/main/java/greenify/server/service/UserService.java
+++ b/src/Server/src/main/java/greenify/server/service/UserService.java
@@ -14,13 +14,13 @@ import org.springframework.web.bind.annotation.ResponseBody;
 
 @Service
 public class UserService {
-    private Logger logger = LoggerFactory.getLogger(UserService.class);
+    @Autowired
+    CalculatorService calculatorService;
 
     @Autowired
     UserRepository userRepository;
 
-    @Autowired
-    CalculatorService calculatorService;
+    private Logger logger = LoggerFactory.getLogger(UserService.class);
 
     /**
      * This method registers the user.
@@ -107,7 +107,7 @@ public class UserService {
     }
 
     /**
-     * This method returns the input value of an input.
+     * This method gets the input value of an input.
      * @param name of the user
      * @param inputName name of the input
      * @return input value
@@ -122,7 +122,7 @@ public class UserService {
     }
 
     /**
-     * This method returns the footprint of a user.
+     * This method gets the footprint of a user.
      * @param name name of the user
      * @return footprint of the user
      */
@@ -132,7 +132,7 @@ public class UserService {
     }
 
     /**
-     * This method returns a JSON of XML with all users.
+     * This method gets a JSON of XML with all users.
      * @return JSON/XML of all users
      */
     @GetMapping(path = "/all")
diff --git a/src/Server/src/test/java/ApplicationTest.java b/src/Server/src/test/java/ApplicationTest.java
index 3e39948..caba9de 100644
--- a/src/Server/src/test/java/ApplicationTest.java
+++ b/src/Server/src/test/java/ApplicationTest.java
@@ -8,6 +8,6 @@ import org.springframework.test.context.junit4.SpringRunner;
 public class ApplicationTest {
 
     @Test
-    public void contextLoads() throws Exception{ }
+    public void contextLoads() { }
 }
 
diff --git a/src/Server/src/test/java/InputValidatorTest.java b/src/Server/src/test/java/InputValidatorTest.java
index e55018d..d80794a 100644
--- a/src/Server/src/test/java/InputValidatorTest.java
+++ b/src/Server/src/test/java/InputValidatorTest.java
@@ -1,5 +1,8 @@
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
 import greenify.server.InputValidator;
-import org.junit.Assert;
 import org.junit.Test;
 
 import java.util.HashMap;
@@ -9,20 +12,20 @@ public class InputValidatorTest {
 
     @Test
     public void validItemIdTest() {
-        InputValidator inputValidator = new InputValidator();
-        Assert.assertEquals(inputValidator.isValidItem("transportation_num_vehicles"), true);
-        Assert.assertEquals(inputValidator.isValidItem("test"), false);
+        new InputValidator();
+        assertEquals(InputValidator.isValidItem("transportation_num_vehicles"), true);
+        assertEquals(InputValidator.isValidItem("test"), false);
     }
 
     @Test
     public void validItemValueTest() {
-        Assert.assertEquals(true, InputValidator
+        assertTrue(InputValidator
                 .isValidItemValue("transportation_num_vehicles", "4"));
-        Assert.assertEquals(false, InputValidator
+        assertFalse(InputValidator
                 .isValidItemValue("transportation_num_vehicles", "3.5"));
-        Assert.assertEquals(false, InputValidator.isValidItemValue( "food_grains", "hello"));
-        Assert.assertEquals(true, InputValidator.isValidItemValue("food_grains", "5"));
-        Assert.assertEquals(true, InputValidator.isValidItemValue("food_grains", "3.5"));
+        assertFalse(InputValidator.isValidItemValue("food_grains", "hello"));
+        assertTrue(InputValidator.isValidItemValue("food_grains", "5"));
+        assertTrue(InputValidator.isValidItemValue("food_grains", "3.5"));
     }
 
     @Test
@@ -54,6 +57,6 @@ public class InputValidatorTest {
                 put("shopping_services", "2413");
             }
         };
-        Assert.assertEquals(InputValidator.getDefaultValues(), map);
+        assertEquals(InputValidator.getDefaultValues(), map);
     }
 }
diff --git a/src/Server/src/test/java/greenify/server/rest/UserControllerTest.java b/src/Server/src/test/java/greenify/server/rest/UserControllerTest.java
index d0784ba..b139f95 100644
--- a/src/Server/src/test/java/greenify/server/rest/UserControllerTest.java
+++ b/src/Server/src/test/java/greenify/server/rest/UserControllerTest.java
@@ -55,8 +55,8 @@ public class UserControllerTest {
                 .andExpect(status().isOk()).andExpect(content().json("{'id':1,'name':'ceren'}"));
     }
 
-    @Test
-    public void setInputTest() {
-
-   }
+    //@Test
+    //public void setInputTest() {
+    //
+    //}
 }
diff --git a/src/Server/src/test/java/greenify/server/service/CalculatorServiceTest.java b/src/Server/src/test/java/greenify/server/service/CalculatorServiceTest.java
index 9c9926f..47fd3fb 100644
--- a/src/Server/src/test/java/greenify/server/service/CalculatorServiceTest.java
+++ b/src/Server/src/test/java/greenify/server/service/CalculatorServiceTest.java
@@ -37,8 +37,7 @@ public class CalculatorServiceTest {
 
         @Bean
         public CalculatorService calculatorService() {
-            CalculatorService calculatorService = new CalculatorService();
-            return calculatorService;
+            return new CalculatorService();
         }
 
         @Bean