Adjust README & javadocs for mapper

Author: andrei-punko

Diff for: README.md

@@ -21,7 +21,7 @@
 - Encryption [example](common/src/main/java/by/andd3dfx/encrypt)
 - Guice usage [example](common/src/main/java/by/andd3dfx/guice)
 - [JMS connector](common/src/main/java/by/andd3dfx/jms) to get queue size by JMX
-- MapStruct mapper [example](common/src/main/java/by/andd3dfx/mapper)
+- ObjectMapper usage [example](common/src/main/java/by/andd3dfx/mapper) with serialization/deserialization object to/from string
 - [Example](common/src/main/java/by/andd3dfx/masking) of annotation-driven masker
 - [Example](common/src/main/java/by/andd3dfx/sockets) of work with sockets
 - [Example](common/src/main/java/by/andd3dfx/testing) of testing classes using Mockito / JMock mocks

Diff for: common/src/main/java/by/andd3dfx/mapper/MapperUtil.java

@@ -7,13 +7,27 @@ public class MapperUtil {
 
     private static ObjectMapper objectMapper = new ObjectMapper();
 
+    /**
+     * Deserialize object from JSON string
+     *
+     * @param jsonString JSON string
+     * @param aClass     object class
+     * @param <T>        type of object class
+     * @return deserialized object of class type T
+     */
     @SneakyThrows
     public static <T> T jsonToObject(String jsonString, Class<T> aClass) {
         return objectMapper.readValue(jsonString, aClass);
     }
 
+    /**
+     * Serialize object to string
+     *
+     * @param object object for serialization
+     * @return string with serialized object
+     */
     @SneakyThrows
-    public static String toJson(Object msa) {
-        return objectMapper.writeValueAsString(msa);
+    public static String toJson(Object object) {
+        return objectMapper.writeValueAsString(object);
     }
 }